cancer screening in the nt - doh digital library: home · breast cancer breast cancer is the most...

DEPARTMENT OF

HEALTH

www.health.nt.gov.au

Cancer screening

in the Northern Territory 2019

Xiaohua Zhang

John Condon

Acknowledgements

Data used in the production of this report was provided by the NT Cervical Screening Register, the BreastScreenNT, the NT

Cancer Register and the Cancer and Screen Unit of the Australian Institution of Health and Welfare. The authors are grateful to

the many people who have assisted in the production of this report, particularly staff of the Cancer Screening NT, including the

manager, Kim Coulter and Medical Officer, Dr Lorraine Lydiard in the final editing of this report and the data manager, Guillermo

Enciso in data preparation. The authors also thank Dr Josette Chor, who coordinated the data collection used in this report and

carried out some initial analysis while worked as Senior Epidemiologist in the NT Department of Health.

© Department of Health, Northern Territory 2019

This publication is copyright. The information in this report may be freely copied and distributed for non-profit purposes such as

study, research, health service management, and public information subject to the inclusion of an acknowledgement of the

source. Reproduction for other purposes requires the written permission of the Chief Executive of the Department of Health,

Northern Territory.

Suggested citation

Zhang X, Condon J. Cancer screening in the Northern Territory 2019. Department of Health, Darwin, 2019.

ISBN 978-0-9924437-8-8

An electronic version is available at:

https://health.nt.gov.au/professionals/Innovation-and-research

General enquiries about this publication should be directed to:

Director, Innovation and Research Branch

Department of Health

PO Box 40596, Casuarina, NT 0811

Phone: (08) 8985 8073

Email: [email protected]

Cancer screening in the NT

of 50

Contents

Summary ................................................................................................................................................. 5

Introduction ............................................................................................................................................ 7

Background ....................................................................................................................................... 7 Data sources ..................................................................................................................................... 8

National Bowel Cancer Screening Program Register ...................................................................... 8 BreastScreenNT .............................................................................................................................. 8 NT Cervical Screening Register ...................................................................................................... 8 NT Cancer Register ......................................................................................................................... 8 Population data ............................................................................................................................... 9

Statistical analysis ............................................................................................................................. 9

Cancer incidence ............................................................................................................................. 9 Participation in cancer screening ..................................................................................................... 9 Age-standardised rates ................................................................................................................... 9 Analysis at regional level ................................................................................................................. 9

Limitations ....................................................................................................................................... 10 HREC approval ................................................................................................................................ 10

Bowel cancer and screening ............................................................................................................... 11

Bowel cancer screening ................................................................................................................... 11

Participation .................................................................................................................................. 11 Test positivity ................................................................................................................................ 12 Follow-up diagnostic assessment .................................................................................................. 13 Detection of adenomas and carcinomas ........................................................................................ 13

Incidence of bowel cancer ............................................................................................................... 14 NT comparison to Australia.............................................................................................................. 15

Breast cancer and screening in women ............................................................................................. 16

Breast cancer screening in women .................................................................................................. 16

Participation .................................................................................................................................. 16 Mode of service delivery (fixed/mobile service) ............................................................................. 20 Detection of breast cancer ............................................................................................................. 22 Time to assessment and treatment ............................................................................................... 23

Incidence of breast cancer in women ............................................................................................... 24

Cervical cancer and screening ............................................................................................................ 25

Cervical screening ........................................................................................................................... 25

Indigenous status recording .......................................................................................................... 25 Participation .................................................................................................................................. 27 Early rescreening .......................................................................................................................... 32 Cytology result .............................................................................................................................. 33 Histology result .............................................................................................................................. 36 High-grade abnormality detection .................................................................................................. 38 Cytology-histology correction......................................................................................................... 40

Incidence of cervical cancer in women ............................................................................................ 43

References ............................................................................................................................................ 45

Appendix. Map of Northern Territory Health Districts ....................................................................... 46

List of tables ......................................................................................................................................... 47

List of figures ........................................................................................................................................ 49


of 50


of 50

Summary

There are government-funded population-based screening programs operating in the Northern Territory (NT) for the prevention or early detection of three types of cancer:

Bowel cancer

Bowel cancer is among the most common cancers for the NT non-Aboriginal population. It occurs mostly in people aged 50 years and over. Bowel cancer incidence is lower for the NT Aboriginal population but has increased considerably over the past three decades.

Regular screening by Faecal Occult Blood Test (with follow-up diagnostic colonoscopy after a positive screening test), can detect bowel cancers early so they can be removed while still small and localised. Screening can also detect adenomas (benign tumours that may later become cancerous) so that they can be removed before developing into cancer.

Between 2007 and 2017 bowel cancer screening participation was lower in the NT than elsewhere in Australia, and lower for Aboriginal than non-Aboriginal people within the NT.

Among those who participated in screening, Aboriginal people had higher prevalence of a positive screening result but were less likely to be followed up by diagnostic assessment after a positive result and less likely to receive treatment after cancer was diagnosed. For those assessed/treated, time to assessment and treatment was longer on average for Aboriginal than non-Aboriginal people.

Breast cancer

Breast cancer is the most common cancer for females in the NT, occurring most commonly in women aged 50 years and over. Breast cancer was uncommon for Aboriginal women in the early 1990s, but incidence increased rapidly since then to be only slightly lower than for non-Aboriginal women in 2006-2015.

Regular breast mammogram screening can identify breast cancer before it causes symptoms and enable early treatment.

Breast screening participation is lower for NT women than for Australian women generally. The participation rate in the NT decreased between 1998-1999 and 2016-2017, due to a considerable drop in participation by non-Aboriginal women; in 2014-2015 participation by 50-69 year-old non-Aboriginal women was 39.8% compared to 52.3% nationally.

Participation was even lower for NT Aboriginal women but has increased since 1998-1999 from 20.7% to 26.7% in 2016-2017. The regular provision of a mobile breast screening service to remote communities contributed to this increase.

For women needing assessment after a positive screening test or treatment after a breast cancer diagnosis, time to assessment and treatment was longer for Aboriginal (most of whom live in remote areas) than non-Aboriginal women.

Cervical cancer

The incidence of cervical cancer is much higher for Aboriginal than non-Aboriginal women. Cervical cancer incidence decreased by more than 50% between 1991-1995 and 2011-2015, by 63% for Aboriginal women and 45% for non-Aboriginal women, indicating the effectiveness of the cervical screening program.

Regular cervical screening can identify infection with oncogenic (i.e. cancer-causing) genotypes of Human Papillomavirus and enable treatment to prevent cervical cancer developing or, if cancer has developed, enable early treatment with a high chance of success.

Cervical screening participation in the NT was the lowest in the country in 2015-2016. When the national cervical screening program commenced in the NT in 1997-1998, participation was much lower for Aboriginal (37%) than non-Aboriginal (64%) women. Since then, participation has increased to 48% for Aboriginal women but decreased to 52% for non-Aboriginal women in 2015-2016, so that


of 50

participation for Aboriginal women is almost the same as for non-Aboriginal women, although both are lower than for Australian women generally.


of 50

Introduction

Background

Cancer is among the most serious health problems and one of the most common causes of death in the NT. It has a major physical, emotional, financial and social impacts on affected patients and their families. Bowel cancer is one of the most commonly diagnosed cancers in Australia, and breast cancer is the most common type of cancer in Australian women [AIHW, 2019a]. Cervical cancer incidence has decreased by more than 50% since the early 1990s and is expected to continue to decrease, but is higher in the NT than elsewhere in Australia and is much higher for Aboriginal than non-Aboriginal women [Condon et al, 2016].

Some types of cancer can be prevented or detected early by regular screening tests. Australia offers government-funded population-based screening programs for three cancers: breast and cervical cancer in women, and bowel cancer for men and women.

The National Bowel Cancer Screening Program (NBCSP) [Cancer Screening, 2019a] invites eligible people without symptoms to screen for bowel cancer using a simple test kit at home. Bowel screening employs the faecal occult blood test (FOBT) to detect microscopic amounts of blood in a bowel motion, which may have come from a bowel cancer or from an adenoma, which is a benign tumour that in some cases develops into cancer. When a screening test is positive (i.e. blood is detected in the faeces), the participant is advised to consult their primary health-care practitioner to organise a follow-up diagnostic assessment (usually a colonoscopy). The NBCSP program aims to prevent bowel cancer by detection and treatment of adenomas, and improve treatment outcomes and survival for those with bowel cancer through early detection of the cancer. The NBCSP operates by sending screening kits to people registered with Medicare at each recommended screening age. When the program commenced in 2006, people were invited to screen at age 55 and 65 years. Since then the recommended screening age range and frequency has increased. Screening is now recommended every second year between the ages of 50 and 74 years.

Breast cancer screening, through mammography, can detect cancer in the breast before it causes any symptoms. Breast screening therefore does not prevent breast cancer but rather detects the cancer early and improves the chance that treatment will successfully cure the disease. Australia has had a national coordinated breast cancer screening program (called “BreastScreen”) since 1991, which provides free mammograms recommended every two years to women aged 50-74 years (50-69 years prior to 2014), and to women aged 40-49 or over 74 years who request it. The screening mammogram can detect changes in the breast tissue that might be due to cancer; women with a positive screening mammogram need to have a further assessment (which may include diagnostic mammography, ultrasound and, if required, a percutaneous biopsy) to determine if they have cancer or not. The majority of women who attend assessment are found not to have an invasive breast cancer or ductal carcinoma in situ (DCIS).

Cancer of the cervix is caused by persistent infection with oncogenic (i.e. cancer-causing) types of Human Papillomavirus (HPV). Cervical screening involves testing cervical cells for infection with oncogenic HPV infection. Treatment after a positive screening test to remove the infected cervical tissue prevents cancer developing. In 1991, Australia introduced a national coordinated cervical screening program that was progressively rolled out in all jurisdictions over several years. The central component of the organised screening program is a cervical screening register that records information about all cervical screening tests for Australian women (except those who ‘opt off’ the register) and provides reminders to women and their screening provider when the next screen is due. Until November 2017, screening was by the Pap test, an indirect test for changes in cervical cells caused by the HPV virus that was recommended every two years for women aged 20-69 years. Since December 2017, screening has been by direct testing for presence of the HPV virus, every five years for women aged 25-74 years [Cancer Screening, 2019b]. This report covers the period 1997 to 2015, before the change to HPV testing.


of 50

This report presents information on the screening programs in the NT, including participation, screening results and outcomes. Screening statistics are presented for the NT as a whole and, when permitted by the availability of reliable data, by Indigenous status and regions with the NT. A comparison of the NT to the national average is also provided where appropriate and when possible.

Data sources

Statistics presented in this report were calculated using data from the NT Cervical Screening Register, BreastScreenNT, the National Bowel Cancer Screening Program, and the NT Cancer Register.

National Bowel Cancer Screening Program Register

The NBCSP Register is maintained by the Commonwealth Department of Human Services and holds information on the NBCSP, managed by the Commonwealth Department of Health in partnership with state and territory governments. Data relating to the NBCSP, in published reports, were obtained from custom analysis conducted by the Australian Institute of Health and Welfare (AIHW). For this report, AIHW provided custom summary tables about screening participation and outcomes for NT residents as at 31 December 2017. Summary tables that contained small numbers were not provided to ensure the privacy of individuals; this limited the level of detail that can be presented for the relatively small NT population.

BreastScreenNT

BreastScreenNT [NT Government, 2019a] commenced mammogram screening in 1994. It performs screening mammograms and follow-up investigations for women with abnormal mammogram results. Mammography is a complex test requiring specialised X-ray equipment and personnel to conduct the test and interpret the results. BreastScreenNT performs almost all screening mammograms in the NT so BreastScreenNT data covers nearly all screened NT women. BreastScreenNT data was used to calculate screening participation rates, the proportion of screening tests that detect an abnormality, and other related statistics.

NT Cervical Screening Register

The NT Cervical Screening Register (CSR) [NT Government, 2019b] commenced operating in 1996 and was operated by the Well Women’s Cancer Screening Service (later becoming Cancer Screening NT) of the NT Department of Health. Cervical screening registers in each state and territory were the central component of the national co-ordinated cervical screening program until December 2017, when the national cervical screening register replaced the eight state/territory registers.

The NT CSR recorded all cervical screening performed in the NT, except for women who chose not to have their cervical screening recorded (‘opt off’). Data from the NT CSR can be used to calculate cervical screening participation, the proportion of cervical screening that detected an abnormality, and other related statistics. Only a small proportion of women choose to opt off, so statistics calculated from NT CSR data include almost all cervical screening performed.

NT Cancer Register

The NT Cancer Register [NT Government, 2019c] is maintained by the Innovation and Research Branch of the NT Department of Health. The Cancer Register collects data about all NT residents who are diagnosed with and/or die from cancer. Information recorded in the register includes demographic details about the person (name, date of birth, sex, Indigenous status, address), clinical information about their cancer diagnosis (date of diagnosis, the body site at which the cancer originated, date and cause of death for those who have died), and pathological features of the cancer (the histological characteristics).


of 50

Population data

Data on the NT population was used as the denominator to calculate cancer incidence rates, and screening participation rates. The population dataset used was Northern Territory Resident Population Estimates by Age, Sex, Indigenous Status and Health District (1971-2017), which is produced by the Innovation and Research Branch [Department of Health, 2018] based on the Australia Bureau of Statistics (ABS) Estimated Resident Population (ERP) at 30 June of each year and stratified by Indigenous status for inter-censual years and by health district based on other data published by ABS.

Statistical analysis

Cancer incidence

Cancer incidence measures the occurrence of cancer in a population in relation to the size of the population. The incidence rate is calculated as the average number of people in the population diagnosed with a cancer in a year divided by the total number of people in the population. The incidence rate can be calculated for all cancers combined or for individual cancer sites. It can also be calculated for the entire population or for sub-groups within the population such as males or females, specific age-groups, Aboriginal or non-Aboriginal people, or residents of specific geographic areas.

Participation in cancer screening

Screening participation is calculated as the proportion of people eligible to be screened who had a screening test.

Age-standardised rates

Many biological phenomena are associated with age, such as cancer incidence (more common in older than younger people, for most cancer types) and abnormal cervical screening (more common in younger than older women). This report presents age-standardised rates, where the calculated rate has been ‘standardised’ to a common age-distribution to adjust for differences in age structure between population groups or changes in age structure over time. This enables direct comparison of rates for groups with different age structures. The age distribution of the total Australian population in 2001 was used as the standard weights when calculating age-standardised rates. The same age-standardisation is applied to screening participation rates.

For rescreening and detection indicators of breast cancer screening, the rates are age-adjusted using the population of women attending a BreastScreen Australia service in 2008 as the standard weights, as specified in the national monitoring report [AIHW, 2019b].

Analysis at regional level

Statistics were provided for NT regions, where the number of events was sufficiently large to allow dis-aggregation into smaller groups. Screening participation and some other screening statistics could be analysed at regional level because a large number of people are screened, so that the numbers available for analysis were sufficiently large to produce reliable statistics for most regions. Cancer incidence rates are present only for the total NT because the number of cases of each cancer type was too small to produce reliable incidence rates for most regions, even with several years data combined.

BreastScreenNT and NT CSR data includes only the current address of participants; i.e. when a woman’s residential address has changed since her previous screen, the previous address is replaced by the new address. As a result, analysis by region was based on the most recent place of residence of each woman, so results for earlier periods were less accurate than for more recent periods. Therefore, this report only provides regional analysis for the most recent period.


of 50

Limitations

Identification of Indigenous status is not complete in the cancer screening data sources used for this report, so statistics presented separately for the Aboriginal and non-Aboriginal populations are not as accurate as would be desired. For screening participation, incomplete identification of Aboriginal women would lead to underestimation of participation rates; the extent of this underestimation is not known. So participation statistics presented in this report for the NT Aboriginal population should be interpreted as the ‘minimum’ estimated participation. Statistics for prevalence of abnormal screening results and follow-up after an abnormal screening test are not underestimated for those people identified as Aboriginal, but it is possible that Aboriginal people, who are not identified as Aboriginal in screening data, may have different prevalence of abnormalities or different follow-up experience.

BreastScreenNT collects self-reported Indigenous status from participants at the time of screening. Identification of Aboriginal women in breast screening data is known to have been incomplete in earlier years but is probably close to complete in more recent years; however, data accuracy has not been formally assessed.

The national bowel screening program asks participants to record their Indigenous status on the information form returned with their screening sample. Nationally, a small percent of the NBSPR participation data have ‘not stated’ Indigenous status, varied from year to year in a range of 2-6%. The missing data is averaged at 3% in the NT.

Nationally, state and territory cervical screening registers (including the NT CSR) did not collect data on Indigenous status because Indigenous status was not included on most laboratory request forms and most laboratory information systems do not have the capacity to record and report it. Between 2010 and 2012 the NT CSR obtained Indigenous status data for most of the women on the register by matching the CSR to the NT Department of Health’s Client Master Index (CMI), which includes accurate Indigenous status data for all clients of any health service operated by the Department. This matching was not continued after 2012, so most women who first screened in the NT after 2012 do not have data on Indigenous status. Data quality of Indigenous status data in the NT CSR after the CMI matching process has not been reported.

NT sources of information about cancer screening may not include all NT residents who have screened. The NBCSPR includes data for all NT residents who participate in bowel screening. However, BreastScreenNT only have data for women who screened in the NT; the results of screening tests for NT residents who had a screening mammogram while interstate were not available to BreastScreenNT. This would affect a small proportion of NT women, predominantly non-Aboriginal women, who screened while interstate; the number of NT women who screened interstate is not known. BreastScreenNT data does not include screening mammograms for NT residents that were performed by private radiologists; this is believed by BreastScreenNT to be a small number of women. The CSR excludes those screened women choosing to ‘opt off’. The NTCSR does not have an estimate of the proportion of women who ‘opt off’; the NSW and Victorian CSRs estimate that the proportion in those states is less than one percent.

An additional limitation of cervical screening data is that the CSR does not have data on colposcopy investigations where a biopsy test was not performed, which could occur if no area of abnormal cervical cells was found by colposcopy. Therefore, analysis of follow-up after an abnormal Pap test will underestimate the proportion of women followed-up by colposcopy to a small extent.

HREC approval

This project was carried out with the approval from the Human Research Ethics Committee of the Northern Territory Department of Health and Menzies School of Health Research (reference number: 2016-2714).


of 50

Bowel cancer and screening

Bowel cancer is among the most common cancers for the NT non-Aboriginal population, especially those aged 50 years and over. Bowel cancer incidence is lower for the NT Aboriginal than the non-Aboriginal population but has increased considerably for the Aboriginal population over the past three decades.

Between 2007 and 2017, screening participation was lower in the NT than elsewhere in Australia. This is not surprising since increased remoteness and lower socioeconomic status have been found to be associated with decreased participation in the bowel cancer screening program.

Within the NT, screening participation is lower for Aboriginal than non-Aboriginal people. Among those who participated in bowel cancer screening, Aboriginal people had higher prevalence of a positive screening result but were less likely to be followed up by diagnostic assessment after a positive result and less likely to receive treatment after cancer was diagnosed. For those assessed/treated, time to assessment and treatment was longer on average for Aboriginal than non-Aboriginal people.

Bowel cancer screening

Participation

In this report, the population-based participation rate to assess the level of overall coverage of screening in the entire population of biennial ages of 50-74 years was used. The population-based participation rate is the number of completed screening tests divided by the estimated resident population (expressed as a percentage). This is different from the program-based participation rate presented in the NBCSP monitoring report [AIHW, 2019b], which is the percentage of people invited to screen who returned a completed screening test. The population-based participation is lower than the program-based participation during the rollout of the program due to the limited number of ages being invited in initial years.

The population-based participation rates of Aboriginal and non-Aboriginal people were estimated using self-reported Indigenous status returned with the screening test. Some of the 842 tests with ‘not stated’ Indigenous status (almost as many as the 949 tests for Aboriginal people) would have been for Aboriginal people. The Aboriginal population-based participation rate was therefore calculated as a range. The minimum rate was calculated using tests identified as being for Aboriginal people; the maximum rate was calculated by allocating a proportion of the ‘non stated’ tests to the Aboriginal or non-Aboriginal groups according to the proportion of Aboriginal and non-Aboriginal people in the NT 50-74 year old population.

For 2007-2017, the average biennial participation rate of the NT was 10.2 per 100 population (Table 1). Participation was similar for males and females and across age groups, but much lower for Aboriginal than non-Aboriginal people (2.0-2.5% vs 11.6-11.8%) in all age-groups, remoteness categories, and genders. There was a tendency of decreased participation with increased remoteness, particularly for the Aboriginal population.


of 50

Table 1. Bowel cancer screening: number of returned screening tests and participation rate, by Indigenous status, NT 2007-2017

Number of returned screening tests Participations per 100 population

Aboriginal Non-Aboriginal Not stated Aboriginal* Non-Aboriginal* Total

All 949 24,672 842 2.0-2.5 11.6-11.8 10.2

Age group: 50-54 278 6,918 230 1.6-2.0 10.6-10.8 9.0

55-59 286 7,485 219 2.3-2.8 13.0-13.3 11.4

60-64 176 4,068 147 2.0-2.5 9.2-9.4 8.3

65-69 144 4,350 172 2.7-3.7 14.9-15.3 13.5

70-74 65 1,851 74 1.9-2.6 11.0-11.3 9.9

Sex: Females 462 12,282 324 1.8-2.2 12.8-13.0 10.8

Males 487 12,390 518 2.2-2.9 10.6-10.9 9.6

Remoteness: Outer regional 506 18,254 565 5.2-6.9 12.5-12.8 12.4

Remote 271 5,225 213 2.3-2.8 10.8-11.1 9.5

Very remote 171 1,160 64 0.7-0.7 6.2-6.4 3.1 Note: * Aboriginal and non-Aboriginal participation ranges were calculated by locating the returned screening tests with Indigenous status ‘not stated’ to each group proportionally as that in the general population in the NT (i.e. 30% of Aboriginal and 70% of non-Aboriginal).

Test positivity

The Faecal Occult Blood Test (FOBT) positivity rate is the number of positive results per 100 valid returned samples, after removing a small proportion of samples that are not suitable for testing.

For the total NT population, 8.6% of valid screening tests were positive for FOBT (Table 2). The positivity rate was higher for: Aboriginal than non-Aboriginal participants; males than females; older than younger age groups; and slightly higher for the first than subsequent screening rounds. There was little difference in positivity rate by remoteness of residence.

Table 2. Bowel cancer screening: number of positive results and positivity rate, by Indigenous status, NT 2007-2017

Positive results / valid screening tests Positivity per 100 valid screening tests

Aboriginal Non-

Aboriginal Not stated Aboriginal Non-

Aboriginal Total

All 92 / 808 1981 / 23574 78 / 547 11.4 8.4 8.6 Screening round:

First 77 / 642 1490 / 17158 79 / 661 12.0 8.7 8.9 Subsequent 15 / 166 491 / 6416 14 / 95 9.0 7.7 7.8

Age group: 50–54 27 / 219 455 / 6286 12 / 111 12.3 7.2 7.5 55–59 22 / 258 524 / 7371 26 / 209 8.5 7.1 7.3 60–64 16 / 148 353 / 3865 14 / 83 10.8 9.1 9.4 65–69 23 / 130 449 / 4285 16 / 105 17.7 10.5 10.8 70–74 0 / 0 200 / 1767 10 / 39 - 11.3 11.6

Sex: Females 41 / 384 826 / 11723 26 / 287 10.7 7.0 7.2 Males 51 / 424 1155 / 11851 67 / 469 12.0 9.7 10.0

Remoteness: Outer regional 48 / 460 1441 / 17468 66 / 512 10.4 8.3 8.4 Remote 24 / 231 450 / 4987 19 / 186 10.2 9.0 9.1 Very remote 20 / 116 87 / 1088 8 / 58 17.6 8.0 9.1


of 50

Follow-up diagnostic assessment

People who received a positive screening result are encouraged to visit their primary health care provider for referral to a specialist for diagnostic assessment, generally by colonoscopy. The assessment rate is the proportion (expressed as a percentage) of people with a positive FOBT who subsequently have a diagnostic colonoscopy. Follow-up diagnostic assessment relies on forms returned from clinicians and is not mandatory. Therefore, differences between participant groups may be due to completeness in form return and should be considered with caution.

In the NT for 2007-2017, the assessment rate was lower for Aboriginal than non-Aboriginal participants (25% vs 55%) (Table 3). The assessment rate was lower in very remote areas than in outer regional and remote areas. The median time to follow-up assessment after a positive FOBT was longer for more remote residents and longer for Aboriginal than non-Aboriginal people (Table 4).

Table 3. Bowel cancer screening: number of follow-up colonoscopy and diagnostic assessment rate, by remoteness and Indigenous status, NT 2007-2017

Number of follow-up colonoscopy Diagnostic assessment rate (%)

Aboriginal Non-

Aboriginal Not stated All Aboriginal Non-

Aboriginal All

Outer regional 11 798 34 843 23 55 54 Remote 7 260 7 274 31 58 56 Very remote n.p. 35 n.p. 40 n.p. 40 34 All areas* 23 1096 41 1160 25 55 54

Notes: * All areas included those with unknown remoteness. n.p. stands for not presented due to a count smaller than 6.

Table 4. Bowel cancer screening: time between positive FOBT result and follow-up colonoscopy, by remoteness and Indigenous status, NT 2007-2017

Note: * All areas included those with unknown remoteness.

Detection of adenomas and carcinomas

The main aim of the bowel screening program is to detect bowel cancer or adenoma. Advanced adenoma has the highest risk of becoming cancerous among all categories of adenomas. Nationally for screening from August 2006 to June 2018, the rate of detection per 100 diagnostic assessments was 7.4% for advanced adenomas and 0.8% for confirmed cancer cases [AIHW, 2019b]. Adenoma and carcinoma detection relies on histopathology forms returned from clinicians and is not mandatory. Therefore, differences between participant groups may be due to completeness in form return and should be considered with caution.

In the NT, 90 cases of advanced adenomas and 9 cases of confirmed cancer were detected through the program during 2007-2017 (Table 5). The rate of detection per 100 assessments was 7.8% for advanced adenomas and 0.8% for confirmed cancer cases, similar to the national rates.

Aboriginal Non-Aboriginal Not stated All

Median days Outer regional 75 63 60 63 Remote 79 84 80 83 Very remote 153 88 98 98 All areas 79 67 65

90th percentile days Outer regional 126 169 167 168 Remote 235 178 175 195 Very remote 302 205 223 223 All areas* 235 174 174


of 50

Table 5. Bowel cancer screening: detection of advanced adenomas and confirmed cancer, by age group, NT 2007-2017

Rate of detected cases

Age at screen

Detected cases

per 100 valid samples

per 100 positive results

per 100 assessments

Adenoma 50–54 15 0.23 3.04 5.98 55–59 27 0.34 4.72 8.21 60–64 15 0.37 3.92 6.94 65–69 23 0.51 4.71 8.65 70–74 10 0.55 4.76 10.20 All ages 90 0.36 4.19 7.76

Cancer All ages 9 0.04 0.42 0.78

Incidence of bowel cancer

The incidence of bowel cancer was relatively stable for the NT non-Aboriginal population between 1991 and 2015 (with fluctuations from one period to another) (Table 6), and was similar to total Australian incidence throughout that period. Incidence was lower for the NT Aboriginal population throughout this period, but increased steadily over time, except for the final period (2011-2015).

Table 6. Bowel cancer incidence: numbers and age-standardised rates in people aged 50-74, by Indigenous status and five-year period, NT 1991-2015

Aboriginal Non-Aboriginal Incidence rate ratio

Cases Rate (95%CI) Cases Rate (95%CI) Non-Aboriginal/Aboriginal

1991-1995 6 28.0 (5.6-50.4) 78 141.5 (106.3-176.6) 5.1 1996-2000 14 59.3 (28.0-90.6) 112 145.5 (115.8-175.2) 2.5 2001-2005 18 67.5 (35.9-99.1) 146 126.4 (103.9-149.0) 1.9 2006-2010 25 85.8 (50.5-121.0) 235 163.3 (140.7-185.9) 1.9 2011-2015 19 43.9 (23.2-64.6) 241 132.6 (115.1-150.1) 3.0

Note: Rates are expressed as number of new cases per 100,000 population and age-standardised using the 2001 Australia Estimated Residents Population.


of 50

Figure 1. Bowel cancer incidence: age-standardised rates in people aged 50-74, by Indigenous status and five-year period, NT 1991-2015 vs Australia 2016

Notes: 1. Rates are expressed as number of new cases per 100,000 population and age-standardised using the 2001 Australia Estimated Residents

Population. 2. The vertical bar indicates 95%CI of the age-standardised rate. 3. Data source for Australia: Cancer in Australia 2019 [AIHW, 2019a].

NT comparison to Australia

The NBCSP reports bowel screening performance measures for Australia as a whole and for each state and territory, most recently for screening conducted in 2016-2017 [AIHW, 2019b]. The program-based participation (i.e. the proportion of invitees who returned a completed screening test) was much lower in the NT than for Australia generally (Table 7). The proportion of positive tests was a little higher in the NT than for Australia overall, but a smaller proportion of people with a positive test in the NT had a diagnostic assessment; almost half of those with a positive test did not have an assessment. For those who did have an assessment, the median time from positive test to assessment was longer in the NT than for Australia overall.

Bowel cancer incidence was lower in the NT than nationally but mortality higher, indicating that survival for people with bowel cancer is lower in the NT than elsewhere, although the time periods were not the same for incidence and mortality calculations.

Table 7. NBCSP performance indicators for people aged 50-74 years, NT and Australia

NT Australia

Screening measures in 2017: Program-based participation (number of returns per 100 invitations) in 2016-2017 28.1 41.3 FOBT positivity (number of positive results per 100 valid samples) 9.3 7.9 Diagnostic assessment (number of assessments per 100 positive results) 51.9 66.4 Days between positive result and diagnostic assessment:

Median 60 52 90th percentile 133 147

Outcome measures: Incidence of bowel cancer (number of cases per 100,000 population)* in 2010-2014 125.6 132.5 Mortality of bowel cancer (number of deaths per 100,000 population)* in 2013-2017 38.5 31.8

Note: * age-standardised rate Source: NBCSP monitoring report, 2019 [AIHW, 2019b]


of 50

Breast cancer and screening in women

Breast cancer is the most common cancer for females in the NT, especially for women aged 50 years and over. Breast cancer was uncommon for Aboriginal women in the 1990s, but their incidence increased rapidly since 1991 to be only slightly lower than non-Aboriginal women in 2006-2015.

Breast screening participation is lower for NT women than for Australian women generally. The NT participation rate decreased between 1998-1999 and 2016-2017, due to a considerable drop in participation by non-Aboriginal women; in 2014-2015 participation by 50-69 year-old non-Aboriginal women was 39.9% compared to 52.3% nationally.

Participation was even lower for NT Aboriginal women but has increased since 1998-1999 to 26.7% in 2016-2017. The regular provision of a mobile breast screening service to remote communities contributed to this increase.

For NT women needing assessment after a positive screening test or treatment after a breast cancer diagnosis, time to assessment and treatment was longer for Aboriginal than non-Aboriginal women.

Breast cancer screening in women

Participation

Between 1 January 1998 and 31 December 2017, 29,298 NT resident women participated in breast screening with a total of 93,543 screens. Most screens (77%) were for women in the target age range of 50-69 years, with another 19% aged 40-49.

For the target age range (50-69 years), the number of women who screened increased from 4,833 in 1998-1999 to 8,712 in 2015-2016 (Table 8), but the age-standardised rate dropped from 45.0% to 37.8% (Table 9) because the population of women eligible for screening also increased. The participation rate in the NT was lower than the national rate [AIHW, 2018a] and this gap increased between 1998-1999 (NT 45.0%, national 56.0%) and 2014-2015 (NT 36.7%, national 54.0%) (Figure 2).

The decrease in the NT participation rate was due to the decreasing participation of non-Aboriginal women from 52.3% to41.1% (Table 9 and Figure 2). The participation rate for Aboriginal women was lower than for non-Aboriginal women but increased from 20.7% to 26.7%. Among the seven health districts, three mostly remote districts (East Arnhem, Barkly and Alice Springs Rural) had lower rates than other districts for both Aboriginal and non-Aboriginal women (Table 10).


of 50

Figure 2. Breast cancer screening: participation rate of women aged 50-69, by Indigenous status, NT 1998-2017

Notes: 1. Rates are expressed as number of women screened as a percentage of the eligible female population and age-standardised using the

2001 Australia Estimated Residents Population. 2. Data source for Australia: BreastScreen Australia monitoring report 2018 [AIHW, 2018a]


of 50

Table 8. Breast cancer screening: number of women screened, by Indigenous status, age group and two-year period, NT 1998-2017

Age group (years) Aged Aged

40-49 50-59 60-69 70+ 40+ years 50-69 years

Aboriginal 1998-1999 193 302 166 53 714 468 2000-2001 264 356 188 75 883 544 2002-2003 274 387 193 69 923 580 2004-2005 216 426 231 50 923 657 2006-2007 189 496 270 48 1,003 766 2008-2009 145 584 318 33 1,080 902 2010-2011 126 649 347 39 1,161 996 2012-2013 455 766 436 67 1,724 1,202 2014-2015 538 745 456 115 1,854 1,201 2016-2017 376 865 545 112 1,898 1,410

Non-Aboriginal 1998-1999 1,855 3,274 1,091 329 6,549 4,365 2000-2001 1,895 3,566 1,235 415 7,111 4,801 2002-2003 1,661 3,584 1,476 470 7,191 5,060 2004-2005 1,462 3,642 1,632 243 6,979 5,274 2006-2007 1,196 3,893 1,900 115 7,104 5,793 2008-2009 1,058 4,111 2,305 143 7,617 6,416 2010-2011 884 4,302 2,673 148 8,007 6,975 2012-2013 1,534 4,468 2,806 285 9,093 7,274 2014-2015 1,209 4,043 2,849 488 8,589 6,892 2016-2017 1,057 4,185 3,117 733 9,092 7,302

All 1998-1999 2,048 3,576 1,257 382 7,263 4,833 2000-2001 2,159 3,922 1,423 490 7,994 5,345 2002-2003 1,935 3,971 1,669 539 8,114 5,640 2004-2005 1,678 4,068 1,863 293 7,902 5,931 2006-2007 1,385 4,389 2,170 163 8,107 6,559 2008-2009 1,203 4,695 2,623 176 8,697 7,318 2010-2011 1,010 4,951 3,020 187 9,168 7,971 2012-2013 1,989 5,234 3,242 352 10,817 8,476 2014-2015 1,747 4,788 3,305 603 10,443 8,093 2016-2017 1,433 5,050 3,662 845 10,990 8,712


of 50

Table 9. Breast cancer screening: participation rate, by Indigenous status and age group, NT 1998-2017

Rate of age group (years) Aged 40+ years Aged 50-69 years

40-49 50-59 60-69 70+ Rate (95%CI) Rate (95%CI)

Aboriginal 1998-1999 6.9 21.8 18.9 10.1 13.6(12.7-14.6) 20.7(19.1-22.4) 2000-2001 8.8 23.1 21.0 13.4 15.7(14.7-16.7) 22.4(20.8-24.1) 2002-2003 8.5 22.4 21.6 11.2 15.2(14.3-16.2) 22.2(20.6-23.8) 2004-2005 6.4 22.3 25.2 7.6 14.2(13.4-15.1) 23.5(21.9-25.0) 2006-2007 5.3 23.5 27.3 6.9 14.4(13.6-15.2) 25.0(23.5-26.6) 2008-2009 3.8 25.0 28.8 4.5 14.2(13.5-15.0) 26.5(25.0-28.0) 2010-2011 3.1 25.4 27.9 5.2 14.1(13.4-14.9) 26.4(25.0-27.8) 2012-2013 10.5 26.8 30.5 8.3 18.0(17.3-18.8) 28.3(27.0-29.7) 2014-2015 11.6 23.4 28.0 13.3 17.9(17.1-18.7) 25.3(24.0-26.5) 2016-2017 7.6 24.6 29.7 12.1 16.8(16.1-17.5) 26.7(25.5-27.9)

Non-Aboriginal 1998-1999 17.5 52.5 52.2 22.9 32.1(34.4-33.7) 52.4(52.3-51.2) 2000-2001 17.1 49.0 50.5 25.6 31.7(33.6-33.0) 49.4(49.6-48.6) 2002-2003 14.7 45.0 50.4 27.1 30.0(32.1-31.4) 46.4(47.4-46.4) 2004-2005 12.8 42.0 47.5 13.5 27.5(27.2-26.6) 43.5(44.3-43.4) 2006-2007 10.4 41.4 45.4 5.6 26.1(24.1-23.6) 42.6(42.9-42.0) 2008-2009 9.0 41.2 48.1 6.3 26.5(24.1-23.6) 43.5(43.8-43.0) 2010-2011 7.3 41.3 49.8 5.8 26.4(23.7-23.2) 44.2(44.3-43.6) 2012-2013 12.5 41.3 47.3 9.8 28.5(25.8-25.4) 43.5(43.6-42.8) 2014-2015 9.9 37.3 44.0 14.7 26.2(24.0-23.6) 39.8(39.9-39.1) 2016-2017 8.8 38.9 44.9 19.4 27.2(25.1-24.7) 41.3(41.1-40.4)

All 1998-1999 15.3 46.9 42.4 19.5 28.0(29.4-28.8) 45.6(45.0-44.1) 2000-2001 15.3 44.5 42.6 22.4 28.1(29.5-28.9) 44.0(43.7-42.8) 2002-2003 13.3 41.0 43.7 23.0 26.7(28.2-27.7) 41.7(42.1-41.2) 2004-2005 11.3 38.4 42.8 11.9 24.5(24.4-24.0) 39.7(40.2-39.3) 2006-2007 9.2 38.1 41.9 5.9 23.4(22.2-21.8) 39.3(39.6-38.8) 2008-2009 7.7 38.2 44.5 5.9 23.7(22.1-21.7) 40.2(40.5-39.8) 2010-2011 6.3 38.2 45.7 5.7 23.5(21.8-21.4) 40.7(40.9-40.2) 2012-2013 12.0 38.3 44.0 9.5 26.2(24.2-23.8) 40.3(40.5-39.8) 2014-2015 10.4 34.1 40.8 14.4 24.2(22.8-22.4) 36.6(36.7-36.1) 2016-2017 8.5 35.4 41.7 18.0 24.6(23.2-22.8) 37.8(37.8-37.2)

Note: Rates are expressed as number of women screened as a percentage of the eligible female population and, for aged 40+ years or 50-69 years, are age-standardised using the 2001 Australia Estimated Residents Population.

Table 10. Breast cancer screening: participation of women aged 50-69, by Indigenous status and health district, NT 2016-2017

Aboriginal Non-Aboriginal All

Number Rate (95%CI) Number Rate (95%CI) Number Rate (95%CI)

Darwin Urban 283 23.3 (20.9-25.7) 5,292 41.4 (41.2-40.3) 5,575 39.7 (39.5-38.7) Darwin Rural 315 40.0 (36.6-43.4) 210 59.7 (63.2-59.1) 545 47.1 (49.7-47.0) Katherine 198 26.6 (23.4-29.8) 412 41.8 (41.5-38.4) 610 35.1 (34.9-32.7) East Arnhem 156 20.7 (17.7-23.6) 131 29.5 (34.3-28.9) 287 24.1 (24.2-21.7) Barkly 69 19.6 (15.5-23.7) 85 26.3 (25.7-20.9) 154 22.5 (22.4-19.2) Alice Springs Urban 202 33.6 (29.8-37.3) 1,091 43.0 (43.2-41.2) 1,293 41.1 (41.2-39.5) Alice Springs Rural 187 22.9 (20.1-25.8) 61 23.0 (23.2-17.6) 248 22.8 (22.8-20.3)

Note: Rates are expressed as number of women screened as a percentage of the eligible female population and age-standardised using the 2001 Australia Estimated Residents Population.


of 50

Mode of service delivery (fixed/mobile service)

BreastScreenNT provides screening services in fixed locations in Darwin, Palmerston and Alice Springs and via a mobile screening bus called ‘Millie’. The mobile service originally visited the towns of Katherine, Tennant Creek and Nhulunbuy with a portable mammography unit which was shipped in containers by road transport or barge. In 2012-13, three trial sites in the remote communities of Wadeye, Jabiru and Alyangula were added. In 2014, the NT Government provided funding for a bus equipped with a mammography machine and staffed with a radiographer, which visits 22 remote communities on a two-year cycle. The provision of the mobile screening service was to overcome the lower participation in more remote areas and provide equity of access.

The number of women who have participated in breast screening has increased in both fixed clinic and mobile services over the last 20 years (Table 11 and Figure 3). Despite a moderate increase in the number of non-Aboriginal women using the mobile service, the proportion of non-Aboriginal women in either service mode was relatively stable. On the contrary, there was a substantial increase in both number and proportion of Aboriginal women using the mobile services especially since 2012-2013 (Table 10 and Figure 3). Therefore, the extension of mobile service to remote communities has resulted in an increase in participation in breast screening among the Aboriginal population.

Table 11. Breast cancer screening: number and proportion of screens using fixed or mobile service, by Indigenous status and two-year period, NT 1998-2017

Aboriginal Non-Aboriginal Mobile (%)

fixed mobile fixed mobile Aboriginal Non-Aboriginal

1998-1999 442 287 6,072 674 39.4 10.0 2000-2001 337 564 6,684 657 62.6 8.9 2002-2003 483 460 6,840 641 48.8 8.6 2004-2005 536 408 6,657 648 43.2 8.9 2006-2007 664 366 6,854 623 35.5 8.3 2008-2009 748 366 7,480 583 32.9 7.2 2010-2011 739 471 7,810 685 38.9 8.1 2012-2013 856 908 8,414 1,133 51.5 11.9 2014-2015 692 1,208 8,002 1,043 63.6 11.5 2016-2017 760 1,181 8,592 975 60.8 10.2


of 50

Figure 3. Breast cancer screening: number of screens using fixed or mobile service, by Indigenous status and two-year period, NT 1998-2017

Figure 4. Breast cancer screening: proportion (%) of screens using mobile service, by Indigenous status and two-year period, NT 1998-2017


of 50

Table 12. Breast cancer screening: numbers of screens and recalls for assessment, by Indigenous status and two-year period, NT 1998-2017


Screens Assessment (%) Screens Assessment (%) Screens Assessment (%)

1998-1999 729 22 (3.0) 6,746 202 (3.0) 7,475 224 (3.0) 2000-2001 901 24 (2.7) 7,341 207 (2.8) 8,242 231 (2.8) 2002-2003 943 37 (3.9) 7,481 291 (3.9) 8,424 328 (3.9) 2004-2005 944 37 (3.9) 7,305 508 (7.0) 8,249 545 (6.6) 2006-2007 1,030 48 (4.7) 7,477 495 (6.6) 8,507 543 (6.4) 2008-2009 1,114 73 (6.6) 8,063 538 (6.7) 9,177 611 (6.7) 2010-2011 1,210 48 (4.0) 8,495 457 (5.4) 9,705 505 (5.2) 2012-2013 1,764 88 (5.0) 9,547 572 (6.0) 11,311 660 (5.8) 2014-2015 1,900 126 (6.6) 9,045 599 (6.6) 10,945 725 (6.6) 2016-2017 1,941 131 (6.7) 9,567 634 (6.6) 11,508 765 (6.6)

Table 13. Breast cancer screening: numbers of screens and recalls for assessment, by health district, NT 2013-2017

Screens Assessments (%)

Darwin Urban 17,753 1,141 (6.4) Darwin Rural 1,899 132 (7.0) Katherine 2,252 162 (7.2) East Arnhem 1,168 92 (7.9) Barkly 445 34 (7.6) Alice Springs Urban 4,523 262 (5.8) Alice Springs Rural 935 57 (6.1)

Notes: 1. Percentage proportion of recalls over screens; 2. Percentage proportion of attendances over recalls.

Detection of breast cancer

The breast cancer detection rate in women aged 50-69 is reported for 1998 to 2017 combined; the rate for shorter periods is not reported because the number of breast cancers diagnosed was too small for more detailed analysis. There were 364 invasive cancers and 94 cases of DCIS diagnosed in screened women in this twenty-year period (Table 14 and Table 15).

In general, the breast cancer detection rate is higher for first-round screens (i.e. for women having their first breast screen) than for subsequent rounds. The first-round detection rates of both invasive cancer and DCIS was lower for the NT than for Australia as a whole, but the detection rates for subsequent rounds was similar. This could be because many women screened for the first time in the NT have migrated to the NT from interstate and therefore their ‘first round’ screening at BreastScreenNT may not actually have been their first breast screen.


of 50

Table 14. Breast cancer screening: invasive breast cancer detection in women aged 50-69, by Indigenous status and screening round, NT 1998-2017

Screening Indigenous NT (1998-2017) Australia (2016)

rounds status Number of cases Rates (95% CI) Rates

First Aboriginal 18 76.3 (38.2-114.5) - Non-Aboriginal 84 93.1 (67.8-118.5) - All 102 88.5 (67.6-109.4) 103.3

Subsequent Aboriginal 27 44.0 (27.4-60.6) - Non-Aboriginal 235 47.6 (41.5-53.7) - All 262 47.2 (41.4-52.9) 50.4

Notes: 1. Rates are the number of women with cases detected per 10,000 women screened and age-adjusted to the population of women attending

BreastScreen Australia Service in 2008. 2. Data source for Australia: BreastScreen Australia monitoring report 2018 [AIHW, 2018a]

Table 15. Breast cancer screening: DCIS detection in women aged 50-69, by Indigenous status and screening round, NT 1998-2017

Screening Indigenous NT (1998-2017) Australia (2016)

rounds status Number of cases Rates (95% CI) Rates

First Aboriginal 4 13.3 (0.0-28.9) - Non-Aboriginal 22 16.1 (7.8-24.4) - All 26 16.2 (8.2-24.2) 27.5

Subsequent Aboriginal 4 6.6 (0.1-13.0) - Non-Aboriginal 64 12.8 (9.7-16.1) - All 68 12.2 (9.3-15.1) 12.7

Notes: 1. Rates are the number of women with cases detected per 10,000 women screened and age-adjusted to the population of women attending

BreastScreen Australia Service in 2008. 2. Data source for Australia: BreastScreen Australia monitoring report 2018 [AIHW, 2018a]

Time to assessment and treatment

The median days from the screen visit date to the assessment date and treatment date were compared for Aboriginal and non-Aboriginal women using time-to-event statistical analysis. Time from screening to assessment was longer for Aboriginal than non-Aboriginal women, as was time from assessment to treatment for women diagnosed with breast cancer. Consequently, for those women with cancer detected, the median days from screen to treatment was significantly longer for Aboriginal women compared to non-Aboriginal women (70 versus 49 days, p<0.001) (Table 16).

Table 16. Breast cancer screening: duration from screening visit to assessment and from assessment to treatment, by Indigenous status, NT 1998-2017

Screening to assessment1 Assessment to treatment2 Screening to treatment2

Aboriginal 34 (24-51) 35 (17-59) 70 (50-97) Non-Aboriginal 25 (18-35) 23 (14-39) 49 (37-69)

log rank test p<0.0001 p<0.01 p<0.001 Notes:

Duration is presented as median days (inter-quartile range). 1. for women with an abnormal screening test

2. for women diagnosed with breast cancer or DCIS


of 50

Incidence of breast cancer in women

For non-Aboriginal women, breast cancer incidence in women aged 50-69 was stable between 1991-1995 and 2001-2015 (with fluctuations from one period to another) (Table 17 and Figure 5). For Aboriginal women, breast cancer incidence was 75% lower than for non-Aboriginal women in 1991-1995 but increased by more than three times to be only 26% lower in 2011-2015. The increased screening participation of Aboriginal women could have contributed to the rise in breast cancer incidence by diagnosing some breast cancers earlier than they would have been diagnosed if left until symptoms occurred. However, this effect would have been small because Aboriginal women’s screening participation increased by only a small amount (from 21% to 27%) and the increase was gradual over twenty years. Table 17. Breast cancer incidence: numbers and age-standardised rates in women aged 50-69, by Indigenous status and five-year period, NT 1991-2015


Cases Rate (95%CI) Cases Rate (95%CI) Aboriginal/Non-Aboriginal

1991-1995 6 60.5 (12.1-108.9) 62 238.3 (177.1-299.5) 0.25 1996-2000 11 100.3 (40.9-159.6) 97 246.6 (194.8-298.3) 0.41 2001-2005 22 166.4 (96.4-236.4) 135 243.1 (200.3-285.9) 0.68 2006-2010 33 196.0 (128.0-263.9) 173 242.7 (205.8-279.5) 0.81 2011-2015 42 194.1 (134.6-253.6) 217 261.2 (226.2-296.2) 0.74


Figure 5. Breast cancer incidence: age-standardised rates in women aged 50-69, by Indigenous status and five-year period, NT 1991-2015 vs Australia




of 50

Cervical cancer and screening

The incidence of cervical cancer is much higher for Aboriginal than non-Aboriginal women. The incidence decreased by more than 50% between 1991-1995 and 2011-2015, by over 60% for Aboriginal women and 55% for non-Aboriginal women, indicating the effectiveness of the cervical screening program.

Cervical screening participation in the NT was the lowest in the country in 2015-2016. When the national cervical screening program commenced in the NT in 1997-1998, participation was much lower for Aboriginal (37%) than non-Aboriginal (64%) women. Since then participation has increased to 48% for Aboriginal women but decreased to 52% for non-Aboriginal women in 2015-2016, so that participation for Aboriginal women is almost the same as for non-Aboriginal women, although both are lower than for Australian women generally.

Cervical screening

Indigenous status recording

Most pathology reports (the primary data source for the CSR) did not include the screened woman’s Indigenous status. In 2010-2012 the NTCSR matched client records to the Department of Health’s CMI to obtain Indigenous status for most women on the register at that time. However, this matching was not continued for women newly registered after 2012. The CMI contains a record for the majority of Aboriginal residents of the NT because of Aboriginal people’s low level of migration to the NT from interstate and their frequent contact with services provided by the Department of Health.

Indigenous status was unknown for 24% of NT women who participated in cervical screening between 1997 and 2016; these women had about 12% of screening tests during that period (Table 18). Unknown Indigenous status was more common for women who first screened after 2012 when the NTCSR ceased matching new women to the CMI (Table 19). Women who first screened after 2012 would be either: women who moved to the NT after 2012 (their first screen recorded on the NTCSR may not have been their first ever screen); women turning 18 after 2012 and commencing screening; older women who were long-term NT residents but had never previously screened (or had not screened since the NTCSR commenced in 1997). The median age at the first screen was much younger in Aboriginal women than non-Aboriginal women; the median age of the unknown group was almost the same as the non-Aboriginal women (Table 19).

Eighty five per cent of the women with unknown Indigenous status who first screened after 2012 resided in the Darwin Urban and Alice Springs Urban districts, where Aboriginal women comprise only a small proportion of the population; only 15% resided in remote areas which have a higher population of Aboriginal Territorians (Table 20). A random sample of 200 women who had their first screening since 2012 was manually checked by the NTCSR staff against the CMI. Only 9.50% (with a 95%CI of 5.47%-13.53%) were recorded as Aboriginal women on the CMI, but this varied considerably by district of residence.

When calculating participation rates for Aboriginal and non-Aboriginal women, those with unknown Indigenous status were classified as non-Aboriginal. Consequently, screening participation statistics in this report overestimate participation for non-Aboriginal women by about one percent while participation for Aboriginal women is underestimated by about seven percent for 2015-2016 (and by a small amount for previous periods), based on the data quality assessment for 200 women with unknown Indigenous status described above.

Therefore, to assign the unknown status to non-Aboriginal category is only considered to be valid for the NT as whole, which results in only a slight overestimation in non-Aboriginal participation and underestimation in Aboriginal participation.


of 50

Table 18. Cevical screening: number of women screened aged 20-69 years, by recorded Indigenous status, NT 1997-2016

Aboriginal Non-Aboriginal Unknown All Reporting period % % % number

1997-1998 17.0 68.6 14.4 31,020 1999-2000 19.6 67.7 12.6 32,248 2001-2002 21.3 67.1 11.6 32,529 2003-2004 21.9 67.9 10.2 31,516 2005-2006 22.9 68.1 9.0 30,917 2007-2008 24.4 67.6 8.0 33,644 2009-2010 24.7 67.6 7.8 35,089 2011-2012 25.9 64.6 9.5 35,364 2013-2014 24.9 58.5 16.7 37,389 2015-2016 25.9 53.8 20.3 37,325

Overall 23.0 64.9 12.1 337,041

Table 19. Cevical screening: women at their first screening, by recorded Indigenous status, NT 1997-2016

Aboriginal Non-Aboriginal Unknown All

%* Age# %* Age# %* Age# number

1997 19.7 28 (22-37) 66.5 35 (27-44) 13.8 31 (25-41) 18,552 1998 17.5 29 (22-38) 67.4 35 (28-44) 15.0 31 (25-40) 14,679 1999 21.8 29 (21-39) 61.3 34 (26-43) 16.9 30 (24-39) 9,402 2000 21.9 27 (19-39) 58.0 31 (25-41) 20.1 29 (24-38) 7,019 2001 19.8 27 (19-38) 58.5 30 (23-39) 21.7 29 (24-37) 5,911 2002 19.6 24 (18-36) 57.0 30 (23-39) 23.4 29 (23-37) 5,350 2003 16.5 23 (18-37) 60.8 29 (23-38) 22.7 29 (23-36) 4,656 2004 17.2 22 (18-36) 59.9 29 (23-38) 22.9 29 (24-38) 4,578 2005 16.6 22 (18-36) 61.1 29 (23-38) 22.3 29 (24-38) 4,314 2006 15.7 22 (18-34) 65.3 29 (23-38) 19.0 29 (23-39) 4,040 2007 15.0 21 (18-35) 66.4 28 (22-37) 18.6 29 (24-37) 4,507 2008 15.5 21 (18-30) 67.1 28 (23-37) 17.4 30 (24-39) 4,668 2009 13.4 21 (19-29) 68.8 29 (23-38) 17.7 31 (25-40) 4,795 2010 15.8 20 (18-27) 65.8 29 (23-38) 18.3 30 (24-40) 4,236 2011 15.5 20 (18-26) 64.9 29 (23-38) 19.7 30 (24-39) 4,387 2012 13.7 21 (19-25) 56.3 29 (23-38) 30.0 29 (24-40) 4,641 2013 9.5 21 (19-28) 41.6 30 (24-38) 48.9 29 (23-37) 5,111 2014 8.6 21 (19-27) 37.9 30 (25-38) 53.5 28 (23-38) 4,886 2015 9.0 21 (19-28) 37.8 30 (24-38) 53.1 29 (23-37) 4,760 2016 8.9 22 (19-28) 36.2 31 (26-39) 54.9 29 (23-37) 4,895

1997-2011 18.1 26 (19-37) 63.8 32 (25-41) 18.1 30 (24-39) 101,094 2012-2016 9.9 21 (19-27) 41.8 30 (24-38) 48.3 29 (23-37) 24,293

Notes: * % is the percentage of all women who first screened in each year (i.e. percent of each row). # Age is expressed as median (interquartile range).


of 50

Figure 6. Cevical screening: proportion (%) of women at their first screening, by recorded Indigenous status, NT 1997-2016

Table 20. Cevical screening: women at their first screening, by recorded Indigenous status and health district, NT 2012-2016

Health district Aboriginal Non-Aboriginal Unknown All

Darwin Urban 583 7,937 10,760 19,280 Darwin Rural 516 268 368 1,152 Katherine 355 793 808 1,956 East Arnhem 473 459 371 1,303 Barkly 148 151 136 435 Alice Springs Urban 361 1,923 1,169 3,453 Alice Springs Rural 291 161 344 796 Unknown 17 19 40 76

NT 2,744 11,711 13,996 28,451

Participation

The NT had the lowest participation rate among all jurisdictions in 2015-2016, 51.8% compared with 56.0% nationally [AIHW, 2018b]. This is consistent with the pattern observed nationally that participation is lower in more remote areas and in areas with lower socioeconomic status, both of which are more common in the NT. The two-year participation rate for the target 20-69 age group in the NT has changed little since 2005-2006, fluctuating between 51% and 53% (Figure 7 and Table 22). Participation rates before 2004 cannot be directly compared with those after 2004 because the hysterectomy fraction used to calculate the denominator of women eligible for screening changed in that year.

The participation rate was much lower for Aboriginal than non-Aboriginal women in the late 1990s, but Aboriginal participation increased from 37% to 48% between 1997-1998 and 2015-2016 while non-Aboriginal participation decreased from 64% to 52%. By 2015-2016 the Aboriginal participation was only a little lower than non-Aboriginal participation. The participation rate is known to be underestimated for Aboriginal women and overestimated for non-Aboriginal women (to a small degree for both, see above); when this is taken into account, it appears that cervical screening participation is similar for Aboriginal and non-Aboriginal women in the NT at about 50%.


of 50

Cervical screening participation varied by age-group in the NT, being highest in the 40-49 age-group and lower in younger and older age-groups (Figure 8). This was similar to the national pattern of variation by age-group, except for the 20-29 age-group. Participation was lower in the NT than nationally in all age-groups except 20-29.

There was considerable variation in participation within the NT. Participation was lower for the Barkly and Alice Springs Rural districts than elsewhere in the NT in the most recent period (2015-2016), whilst the Darwin Rural district had the highest participation (Table 24 and Figure 9).

Figure 7. Cevical screening: age-standardised participation rate of women aged 20-69 years, by Indigenous status, NT 1997-2016


2001 Australia Estimated Residents Population. 2. Data source for Australia: Cervical Screening in Australia 2018 [AIHW, 2018b]. 3. Rates from 1997-1998 to 2003-2004 cannot be directly compared with rates from 2005-2006 onwards, because a different source of

hysterectomy fractions was used to adjust the population.


of 50

Table 21. Cervical screening: women screened, by Indigenous status and age group, NT 1997-2016

Age group (years) Aged All

<20 20-29 30-39 40-49 50-59 60-69 70+ 20-69 years ages

Aboriginal 1997-1998 925 2417 1606 824 314 119 29 5280 6234 1999-2000 1060 2647 1930 1105 465 188 32 6335 7427 2001-2002 1110 2749 2221 1199 567 186 37 6922 8069 2003-2004 1002 2541 2256 1268 610 217 37 6892 7931 2005-2006 799 2595 2259 1344 647 233 23 7078 7900 2007-2008 796 2964 2543 1605 820 278 29 8210 9035 2009-2010 670 3037 2558 1770 957 331 28 8653 9351 2011-2012 646 3138 2548 2003 1085 376 48 9150 9844 2013-2014 414 2907 2585 2166 1198 440 34 9296 9744 2015-2016 308 2865 2683 2290 1314 519 42 9671 10021

Non-Aboriginal 1997-1998 1097 8248 8319 5919 2566 688 160 25740 26997 1999-2000 1037 7591 8267 6138 3092 825 187 25913 27137 2001-2002 1068 7015 8069 6191 3370 962 192 25607 26867 2003-2004 1002 6369 7547 6070 3581 1057 154 24624 25780 2005-2006 860 5958 6997 5890 3779 1215 122 23839 24821 2007-2008 951 6429 7203 6076 4228 1498 142 25434 26527 2009-2010 837 6554 7248 6320 4522 1792 142 26436 27415 2011-2012 747 6488 7004 6156 4583 1983 131 26214 27092 2013-2014 862 7063 7771 6229 4807 2223 157 28093 29112 2015-2016 740 6994 7808 5990 4577 2285 172 27654 28566

All 1997-1998 2022 10665 9925 6743 2880 807 189 31020 33231 1999-2000 2097 10238 10197 7243 3557 1013 219 32248 34564 2001-2002 2178 9764 10290 7390 3937 1148 229 32529 34936 2003-2004 2004 8910 9803 7338 4191 1274 191 31516 33711 2005-2006 1659 8553 9256 7234 4426 1448 145 30917 32721 2007-2008 1747 9393 9746 7681 5048 1776 171 33644 35562 2009-2010 1507 9591 9806 8090 5479 2123 170 35089 36766 2011-2012 1393 9626 9552 8159 5668 2359 179 35364 36936 2013-2014 1276 9970 10356 8395 6005 2663 191 37389 38856 2015-2016 1048 9859 10491 8280 5891 2804 214 37325 38587


of 50

Table 22. Cervical screening: age-specific and age-standardised participation rates of women aged 20-69 years, by Indigenous status, NT 1997-2016

Rate of age group (years) Aged 20-69 years

20-29 30-39 40-49 50-59 60-69 Rate (95%CI)

Aboriginal 1997-1998 45.6 41.1 35.6 32.8 20.1 36.7 (35.7, 37.6) 1999-2000 49.7 46.6 43.7 44.0 31.1 44.3 (43.3, 45.3) 2001-2002 50.4 50.9 44.0 48.1 30.6 46.4 (45.4, 47.3) 2003-2004 45.0 48.6 43.6 44.2 34.3 44.0 (43.1, 44.9) 2005-2006 44.1 46.2 43.3 40.6 34.1 42.5 (41.7, 43.4) 2007-2008 48.7 51.5 48.6 46.5 36.8 47.5 (46.6, 48.3) 2009-2010 48.2 52.3 50.2 49.3 38.9 48.7 (47.9, 49.5) 2011-2012 48.7 51.6 53.4 50.9 39.0 49.7 (48.9, 50.5) 2013-2014 44.4 50.3 54.1 50.0 39.7 48.5 (47.7, 49.3) 2015-2016 43.1 50.2 53.8 49.4 41.4 48.3 (47.6, 49.1)

Non-Aboriginal 1997-1998 66.1 67.7 65.5 61.7 51.0 63.7 (63.2, 64.3) 1999-2000 62.5 65.6 65.3 63.1 54.6 62.9 (62.4, 63.5) 2001-2002 62.4 63.2 63.5 60.5 52.2 61.1 (60.6, 61.6) 2003-2004 60.4 61.6 60.6 57.1 47.4 58.6 (58.1, 59.1) 2005-2006 54.5 58.0 57.6 52.3 44.2 54.3 (53.8, 54.8) 2007-2008 54.7 58.6 59.0 55.1 46.0 55.5 (55.1, 56.0) 2009-2010 51.2 56.5 59.9 55.8 48.6 54.9 (54.4, 55.4) 2011-2012 49.3 54.1 56.9 54.5 48.6 53.0 (52.6, 53.5) 2013-2014 49.9 56.2 57.3 55.8 49.2 54.1 (53.7, 54.5) 2015-2016 49.7 53.1 55.7 53.5 47.1 52.4 (51.9, 52.8)

All 1997-1998 60.0 61.3 59.4 56.3 41.6 57.2 (56.7, 57.7) 1999-2000 58.6 60.9 60.7 59.7 47.9 58.4 (58.0, 58.9) 2001-2002 58.5 60.1 59.3 58.4 46.8 57.5 (57.1, 58.0) 2003-2004 55.0 58.0 56.7 54.7 44.5 54.8 (54.3, 55.2) 2005-2006 50.9 54.6 54.2 50.1 42.2 51.3 (50.9, 51.7) 2007-2008 52.6 56.5 56.5 53.5 44.3 53.5 (53.1, 53.9) 2009-2010 50.2 55.4 57.4 54.5 46.8 53.4 (53.0, 53.8) 2011-2012 49.1 53.4 56.0 53.8 46.8 52.2 (51.8, 52.6) 2013-2014 48.2 54.6 56.4 54.5 47.4 52.6 (52.3, 53.0) 2015-2016 47.6 52.3 55.1 52.5 45.9 51.1 (50.8, 51.5)

Notes: 1. Rates are expressed as number of women screened as a percentage of the eligible female population and, for aged 20-69 years, are age-

standardised using the 2001 Australia Estimated Residents Population. 2. Rates from before 2003-2004 cannot be directly compared with rates from 2005-2006 onwards, because a different source of

hysterectomy fractions was used to adjust the population.

Table 23. Cervical screening: effect of possible missing Aboriginal participants on participation of women aged 20-69 years, by Indigenous status, NT 2011-2016

Known

Aboriginal Unknown status Missing

Aboriginal* Known & missing

Aboriginal

screens participation% 1st screen <2012 1st screen 2012+ screens participation%

2011-2012 9,150 49.7 2,054 1,298 123 ( 71-176) 50.4 (50.1-50.7) 2013-2014 9,296 48.5 1,279 4,954 471 (271-670) 51.0 (49.9-52.0) 2015-2016 9,671 48.3 958 6,612 628 (362-895) 51.4 (50.1-52.8)

Note: * Missing Aboriginal are calculated from the proportion of confirmed Aboriginal in the random sample being checked for women started screen since 2012, which is 9.50 (with a 95%CI of 5.47-13.53).


of 50

Figure 8. Cervical screening: age-specific participation rate of women aged 20-69 years, NT and Australia 2015-2016

Notes: 1. Rates are expressed as number of women screened as a percentage of the eligible female population. 2. Australian rates of 10-year age groups are estimated as the mean of participation rates of 5-year age groups. 3. Data source for Australia: Cervical Screening in Australia 2018 [AIHW, 2018b].

Table 24. Cervical screening: number and age-standardised participation rate of women aged 20-69 years, by health district, NT 2015-2016

Health district Participants Rate (95%CI)

Darwin Urban 22,493 52.6 (52.1-53.1) Darwin Rural 2,502 58.2 (56.7-59.8) Katherine 3,005 51.2 (49.9-52.5) East Arnhem 2,257 45.2 (43.7-46.8) Barkly 710 35.5 (33.3-37.6) Alice Springs Urban 4,738 51.6 (50.5-52.6) Alice Springs Rural 1,509 39.9 (38.2-41.5)

Note: Rates are expressed as number of women screened as a percentage of the eligible female population and age-standardised using the 2001 Australia Estimated Residents Population.


of 50

Figure 9. Cervical screening: age-standardised participation rate of women aged 20-69 years, by health district, NT 2015-2016


2001 Australia Estimated Residents Population. 2. The vertical bar indicates 95%CI of the age-standardised rate.

Early rescreening

The ‘early rescreening’ indicator measures the proportion of women who had a repeat Pap test earlier than was recommended. It was calculated as the percentage of women who had a Pap test within 21 months of a normal Pap test (and had no cervical abnormalities in the preceding three years). The early rescreening indicator is a measure of ‘over-screening’ (i.e. screening more frequently than is necessary).

The national cervical screening report indicates that early rescreening is less common in the NT than in other states and territories [AIHW, 2018]. The early screening calculation in this report is slightly different to that for the national report, which is based on a cohort of women screened in February each year, [AIHW, 2018]. In this report, early rescreening was calculated for the cohort of women who screened in the entire year because of the small number of women screening in any one month in the NT. Consequently, early rescreening statistics in this report cannot be directly compared with national statistics.

Early rescreening was more common for Aboriginal than non-Aboriginal women in the NT but more than halved between 1997 and 2015 for both groups, decreasing from 26% of women who screened in 1997 (Aboriginal 30%, non-Aboriginal 25%) to 10% of women who screened 2015 (Aboriginal 13%, non-Aboriginal 9%) (Figure 10).

Early rescreening was compared for districts within the NT for women who screened in the two-year period 2014-2015 (Table 25). Early rescreening was a little more common in the three districts (East Arnhem, Barkly and Alice Springs Rural) with a higher proportion of Aboriginal people in the population.


of 50

Figure 10. Cervical screening: proportion (%) of early rescreening in screened women aged 20-69 years, by year of index screening and Indigenous status, NT 1997-2015

Table 25. Cervical screening: proportion of early rescreening in screened women aged 20-69 years, by number of repeats and health district, NT, index screenings of 2014-2015

Health district Total screenings Early rescreening 1 repeat 2 or more repeats

Darwin Urban 20,447 9.4% 9.1% 0.3% Darwin Rural 2,107 9.9% 9.5% 0.3% Katherine 2,623 10.8% 10.0% 0.8% East Arnhem 2,047 12.0% 11.3% 0.7% Barkly 631 11.4% 10.0% 1.4% Alice Springs Urban 4,453 10.2% 9.6% 0.7% Alice Springs Rural 1,461 12.7% 12.1% 0.5%

NT 33,857 10.0% 9.6% 0.5%

Cytology result

Abnormal cytology results, both low-grade and high-grade, were more common in younger than older women (Figure 11 and Table 26). The prevalence of high-grade abnormal screening results (among screened women) decreased over the past twenty years for Aboriginal women but not for non-Aboriginal women (Figure 12), but was still higher for Aboriginal than non-Aboriginal women (2.0% compared to 1.3%) in 2015-2016. ‘Unsatisfactory’ screening tests were more common in the Central than Top End region (Table 29).


of 50

Figure 11. Cervical screening: age-specific prevalence of abnormal cytology results in screened women aged 20-69 years, NT 2015-2016

Note: Prevalence are expressed as the number of tests in each result category as a percentage of total cytology tests.

Table 26. Cervical screening: age-specific prevalence of abnormal cytology results in screened women aged 20-69 years, by two-year period, NT 1997-2016

Age-group (years)

Period 20-29 30-39 40-49 50-59 60-69

Low-grade abnormalities 1997-1998 11.6 7.6 7.6 7.1 3.5 1999-2000 10.6 6.3 5.9 4.0 3.0 2001-2002 13.1 7.7 7.0 5.1 4.4 2003-2004 11.3 5.4 4.2 3.7 2.4 2005-2006 11.6 5.8 4.1 2.8 2.3 2007-2008 9.5 4.4 3.3 2.3 2.4 2009-2010 7.6 3.9 2.5 1.8 1.4 2011-2012 8.5 4.9 3.9 2.7 2.0 2013-2014 9.8 6.2 4.8 3.1 1.8 2015-2016 10.2 6.2 5.1 4.1 2.5

High-grade abnormalities 1997-1998 2.9 2.3 1.5 1.3 0.9 1999-2000 2.8 1.9 1.3 1.0 0.9 2001-2002 3.3 1.9 1.2 1.0 1.3 2003-2004 2.4 1.7 0.9 0.6 0.8 2005-2006 2.9 2.0 1.1 0.7 1.1 2007-2008 3.4 2.3 1.2 0.7 0.9 2009-2010 3.3 2.0 1.3 1.0 0.7 2011-2012 3.3 2.3 1.1 0.9 0.5 2013-2014 2.9 1.9 1.1 0.6 0.5 2015-2016 2.3 2.2 1.0 0.8 0.8

Note: Prevalence are expressed as the number of tests in each result category as a percentage of total cytology tests.

0

2

4

6

8

10

12

20-29 30-39 40-49 50-59 60-69

Age-group

Low-grade

High-grade


of 50

Table 27. Cervical screening: age-standardised prevalence of cytology result category in screened women aged 20-69 years, by two-year period, NT 2015-2016

Age-standardised rate (95%CI) Total

Unsatis- Low-grade High-grade All number factory Negative abnormalities abnormalities abnormalities of tests

1997-1998 2.1 (1.9-2.3) 88.1 (87.7-88.5) 7.9 (7.6-8.2) 1.9 (1.7-2.0) 9.8 (9.5-10.1) 39,113 1999-2000 2.3 (2.2-2.5) 89.6 (89.3-90.0) 6.3 (6.1-6.6) 1.7 (1.5-1.8) 8.0 (7.7- 8.3) 39,785 2001-2002 3.2 (3.0-3.4) 87.1 (86.7-87.4) 7.8 (7.5-8.1) 1.8 (1.7-2.0) 9.7 (9.4-10.0) 40,200 2003-2004 2.0 (1.8-2.1) 91.0 (90.7-91.3) 5.7 (5.5-5.9) 1.3 (1.2-1.4) 7.0 (6.8- 7.3) 37,840 2005-2006 1.7 (1.6-1.9) 90.9 (90.6-91.2) 5.7 (5.5-6.0) 1.6 (1.5-1.8) 7.4 (7.1- 7.6) 36,102 2007-2008 2.0 (1.9-2.2) 91.5 (91.2-91.8) 4.6 (4.4-4.8) 1.8 (1.7-1.9) 6.4 (6.2- 6.7) 38,292 2009-2010 2.3 (2.1-2.4) 92.2 (92.0-92.5) 3.7 (3.5-3.9) 1.8 (1.6-1.9) 5.5 (5.3- 5.7) 39,621 2011-2012 2.4 (2.2-2.6) 91.1 (90.8-91.4) 4.7 (4.5-4.9) 1.7 (1.6-1.9) 6.5 (6.2- 6.7) 39,520 2013-2014 1.3 (1.2-1.4) 91.7 (91.4-91.9) 5.5 (5.3-5.8) 1.5 (1.4-1.6) 7.1 (6.8- 7.3) 41,576 2015-2016 1.4 (1.3-1.5) 91.0 (90.8-91.3) 6.0 (5.8-6.2) 1.5 (1.4-1.6) 7.5 (7.3- 7.8) 41,384

Note: Prevalence are expressed as the number of tests in each result category as a percentage of total cytology tests and age-standardised using the 2001 Australia Estimated Residents Population.

Figure 12. Cervical screening: age-standardised prevalence of cytology high-grade abnormality in screened women aged 20-69 years, by two-year period and Indigenous status, NT 1997-2016



of 50

Table 28. Cervical screening: age-standardised prevalence of cytology high-grade abnormality in screened women aged 20-69 years, by two-year period and Indigenous status, NT 1997-2016

Age-standardised rate (95%CI)


1997-1998 3.1 (2.6-3.6) 1.6 (1.5-1.8) 1.9 (1.7-2.0) 1999-2000 2.9 (2.4-3.3) 1.4 (1.2-1.5) 1.7 (1.5-1.8) 2001-2002 2.8 (2.3-3.2) 1.6 (1.5-1.8) 1.8 (1.7-2.0) 2003-2004 2.4 (2.0-2.8) 1.1 (0.9-1.2) 1.3 (1.2-1.4) 2005-2006 2.8 (2.3-3.2) 1.3 (1.2-1.4) 1.6 (1.5-1.8) 2007-2008 2.9 (2.5-3.3) 1.4 (1.3-1.5) 1.8 (1.7-1.9) 2009-2010 2.5 (2.2-2.8) 1.5 (1.4-1.7) 1.8 (1.6-1.9) 2011-2012 2.3 (2.0-2.6) 1.6 (1.4-1.7) 1.7 (1.6-1.9) 2013-2014 2.0 (1.7-2.3) 1.3 (1.2-1.5) 1.5 (1.4-1.6) 2015-2016 2.0 (1.8-2.3) 1.3 (1.2-1.5) 1.5 (1.4-1.6)


Table 29. Cervical screening: age-standardised prevalence of cytology result category in screened women aged 20-69 years, by health district, NT 2012-2016


Unsatis- Low-grade High-grade All number

factory Negative abnormalities abnormalities abnormalities of tests

Darwin Urban 1.2 (1.1-1.3) 91.5 (91.3-91.7) 5.7 (5.5-5.9) 1.5 (1.4-1.6) 7.2 (7.0-7.4) 60,998 Darwin Rural 1.6 (1.3-1.9) 90.7 (90.0-91.4) 6.0 (5.4-6.5) 1.8 (1.5-2.1) 7.7 (7.1-8.4) 6,673 Katherine 1.4 (1.1-1.6) 91.1 (90.5-91.7) 5.7 (5.2-6.2) 1.8 (1.5-2.1) 7.5 (6.9-8.1) 8,187 East Arnhem 1.4 (1.1-1.7) 91.2 (90.5-91.8) 5.8 (5.2-6.3) 1.6 (1.3-1.9) 7.4 (6.8-8.0) 6,482 Barkly 3.5 (2.7-4.4) 88.8 (87.4-90.2) 5.8 (4.8-6.8) 1.9 (1.3-2.5) 7.7 (6.6-8.8) 2,227 Alice Springs Urban 2.5 (2.2-2.7) 90.9 (90.4-91.3) 5.5 (5.1-5.9) 1.2 (1.0-1.4) 6.7 (6.3-7.1) 13,678 Alice Springs Rural 2.9 (2.3-3.4) 90.3 (89.4-91.3) 4.9 (4.2-5.6) 1.9 (1.4-2.4) 6.8 (5.9-7.6) 4,335

Top End 1.3 (1.2-1.4) 91.4 (91.2-91.6) 5.7 (5.5-5.9) 1.6 (1.5-1.7) 7.3 (7.1-7.5) 82,340 Central 2.7 (2.4-2.9) 90.6 (90.2-91.0) 5.4 (5.1-5.7) 1.4 (1.2-1.5) 6.7 (6.4-7.1) 20,240


Histology result

Between four and six percent of screened women had a follow-up histology test after an abnormal screening test; this proportion was stable (with year to year fluctuation) between 1997 and 2016 (Table 30). The proportion of histology tests that reported a high-grade abnormality increased while the proportion that reported a LGA decreased from 2005-2006; this was likely the result of changes in 2006 to the guidelines for management of abnormal screening tests, which reduced the indications for colposcopy and biopsy investigation after an LGA result.

Table 30. Cervical screening: histology test as proportion (%) of cytology tests in screened women aged 20-69 years, by two-year period and age group, NT 1997-2016

Age-group (years) Aged 20-69

20-29 30-39 40-49 50-59 60-69 years

1997-1998 7.8 5.7 4.7 4.8 3.3 6.1 1999-2000 7.1 4.9 4.1 2.7 3.4 5.2 2001-2002 7.0 4.5 4.5 3.0 2.2 5.0 2003-2004 6.3 4.3 4.4 3.2 3.4 4.8 2005-2006 6.6 4.7 4.9 3.5 2.4 5.0 2007-2008 5.9 5.3 5.7 3.7 2.9 5.2 2009-2010 6.4 5.1 5.3 4.5 2.9 5.3 2011-2012 5.8 5.3 4.8 3.9 2.9 5.0 2013-2014 5.4 4.3 4.6 3.4 2.1 4.4 2015-2016 4.9 4.9 4.9 3.6 2.9 4.6


of 50

Table 31. Cervical screening: age-specific prevalence of histology result category in histology-tested women aged 20-69 years, by two-year period, NT 1997-2016

Age-group (years)

Period 20-29 30-39 40-49 50-59 60-69

Low-grade abnormalities 1997-1998 38.6 30.7 25.1 23.1 12.9 1999-2000 33.4 24.2 20.5 18.1 15.4 2001-2002 38.0 30.2 31.6 19.3 10.3 2003-2004 34.2 30.1 21.5 14.8 18.4 2005-2006 30.4 21.7 15.0 13.2 7.7 2007-2008 21.5 21.7 13.6 14.0 10.5 2009-2010 24.2 21.7 14.7 13.9 9.1 2011-2012 23.6 22.9 17.5 14.0 13.7 2013-2014 27.3 24.4 20.0 13.7 16.4 2015-2016 26.4 23.6 20.6 11.8 11.4

High-grade abnormalities 1997-1998 33.7 31.8 19.1 17.2 9.7 1999-2000 34.9 33.4 23.3 19.0 20.5 2001-2002 42.9 31.9 21.8 16.4 31.0 2003-2004 42.6 32.4 16.2 12.9 12.2 2005-2006 51.3 43.8 17.4 13.8 33.3 2007-2008 58.5 48.8 26.8 11.1 22.8 2009-2010 58.3 46.9 24.8 16.1 12.1 2011-2012 54.4 42.5 20.5 16.0 6.8 2013-2014 49.0 46.4 20.4 13.7 8.2 2015-2016 53.5 42.9 18.2 14.8 17.0

Invasive carcinomas 1997-1998 0.1 0.7 3.0 2.4 6.5 1999-2000 0.2 1.1 0.8 3.4 2.6 2001-2002 0.5 1.0 1.9 1.4 0.0 2003-2004 0.3 0.6 1.6 1.3 0.0 2005-2006 0.1 2.5 1.0 2.9 2.6 2007-2008 0.8 1.4 2.4 1.4 7.0 2009-2010 0.0 1.6 0.8 4.5 0.0 2011-2012 0.3 1.6 2.8 2.1 8.2 2013-2014 0.7 0.0 2.6 2.7 1.6 2015-2016 0.0 0.7 2.5 2.2 2.3

Note: Prevalence are expressed as the number of tests in each result category as a percentage of total histology tests.

Table 32. Cervical screening: age-standardised prevalence of histology result category in histology-tested women aged 20-69 years, by two-year period, NT 1997-2016


Low-grade High-grade Invasive All number abnormalities abnormalities carcinomas abnormalities of tests

1997-1998 26.7 (24.7-28.8) 24.9 (21.4-28.4) 1.7 (0.9-2.6) 53.4 (49.6-57.1) 2,380 1999-2000 23.2 (20.9-25.6) 27.1 (24.6-29.6) 1.5 (0.6-2.4) 51.8 (48.9-54.8) 2,063 2001-2002 27.5 (25.3-29.8) 29.3 (26.4-32.2) 1.2 (0.6-1.8) 58.0 (54.9-61.2) 2,015 2003-2004 24.9 (22.5-27.3) 25.1 (22.8-27.4) 0.7 (0.3-1.1) 50.7 (47.9-53.6) 1,799 2005-2006 18.8 (16.8-20.7) 32.1 (29.7-34.5) 1.7 (0.9-2.6) 52.6 (50.2-55.1) 1,817 2007-2008 17.0 (15.2-18.9) 35.6 (33.4-37.7) 2.2 (1.2-3.2) 54.8 (52.4-57.2) 1,988 2009-2010 17.3 (15.7-18.9) 34.5 (32.4-36.5) 1.4 (0.9-2.0) 53.2 (51.0-55.4) 2,092 2011-2012 18.9 (17.0-20.7) 30.3 (28.5-32.2) 2.4 (1.5-3.4) 51.6 (49.3-53.9) 1,962 2013-2014 20.7 (18.7-22.7) 29.9 (27.8-32.0) 1.4 (0.8-2.1) 52.0 (49.7-54.4) 1,817 2015-2016 19.7 (18.0-21.5) 31.0 (28.9-33.1) 1.3 (0.7-1.9) 52.0 (49.8-54.2) 1,889

Note: Prevalence are expressed as the number of tests in each result category as a percentage of total histology tests and age-standardised using the 2001 Australia Estimated Residents Population.


of 50

Figure 13. Cervical screening: age-standardised prevalence of abnormal histology results in histology-tested women aged 20-69 years, by two-year period, NT 1997-2016

Note: Prevalence are expressed as the number of tests in each result category as a percentage of total histology tests and age-standardised using the 2001 Australia Estimated Residents Population.

High-grade abnormality detection

The detection of high-grade abnormalities is an indicator of the National Cervical Screening Program for assessing how well the program detects these abnormalities. The high-grade abnormality detection rate is calculated as the proportion of screened women with a high-grade abnormality confirmed by histology test over the total women being screened.

The high-grade abnormality detection rate was higher in younger than older age-groups, and higher in Aboriginal than non-Aboriginal women (Table 33). For non-Aboriginal women the age-standardised detection rate was stable over time, fluctuating between 9 and 13 per 1,000 women screened. However, the detection rate for Aboriginal women decreased from about double the non-Aboriginal rate in the late 1990s to be similar to the non-Aboriginal rate in recent years.

0

5

10

15

20

25

30

35

40

1997-1998

1999-2000

2001-2002

2003-2004

2005-2006

2007-2008

2009-2010

2011-2012

2013-2014

2015-2016

Low-grade

High-grade


of 50

Figure 14. Cervical screening: age-standardised high-grade abnormality detection rates in screened women aged 20-69 years, by Indigenous status and two-year period, NT 1997-2016

Note: Rates are expressed as number of women with high-grade abnormality detected by histology per 1,000 women screened and age-standardised using the 2001 Australia Estimated Residents Population.


of 50

Table 33. Cervical screening: age-specific and age-standardised high-grade abnormality detection rates in screened women aged 20-69 years, by Indigenous status and two-year period, NT 1997-2016

Rate of age group (years) Aged 20-69 years

20-29 30-39 40-49 50-59 60-69 number rate (95%CI)

Aboriginal 1997-1998 30.6 34.1 14.9 19.4 0.0 173 21.6 (17.6-25.5) 1999-2000 28.8 26.2 19.8 11.5 9.9 182 20.9 (17.0-24.7) 2001-2002 28.8 15.2 13.3 12.6 15.2 161 17.5 (13.9-21.1) 2003-2004 23.5 16.6 9.2 5.9 17.6 134 14.3 (11.2-17.4) 2005-2006 34.1 21.8 10.8 11.3 20.7 187 19.9 (16.3-23.5) 2007-2008 36.3 26.1 22.4 4.5 16.7 246 22.6 (19.2-25.9) 2009-2010 31.4 21.2 16.8 9.7 2.8 211 18.1 (15.5-20.7) 2011-2012 22.9 15.9 6.9 6.8 2.5 148 11.9 ( 9.9-13.9) 2013-2014 15.7 15.0 6.3 6.2 2.1 117 10.1 ( 8.1-12.0) 2015-2016 14.1 16.6 8.5 7.1 9.1 129 11.2 ( 9.2-13.3)

Non-Aboriginal 1997-1998 19.3 11.8 6.5 5.5 4.0 354 10.0 ( 8.9-11.2) 1999-2000 18.5 11.5 6.1 3.2 3.3 320 9.3 ( 8.2-10.5) 2001-2002 24.4 11.3 7.4 2.4 5.7 361 11.0 ( 9.8-12.2) 2003-2004 24.2 10.6 5.3 3.3 1.7 313 9.9 ( 8.8-11.1) 2005-2006 24.9 13.7 5.2 2.7 3.1 317 11.0 ( 9.7-12.2) 2007-2008 22.9 16.0 8.1 3.3 1.9 355 11.6 (10.4-12.8) 2009-2010 28.0 15.7 8.5 5.0 2.7 408 13.2 (11.9-14.5) 2011-2012 24.9 17.6 7.8 3.9 1.5 379 12.3 (11.1-13.5) 2013-2014 22.1 14.7 8.2 2.7 1.3 362 10.7 ( 9.6-11.8) 2015-2016 21.4 16.5 6.3 3.5 2.5 361 10.9 ( 9.8-12.1)

All 1997-1998 22.0 15.5 7.5 7.1 3.4 527 11.9 (10.8-13.1) 1999-2000 21.2 14.4 8.2 4.3 4.5 502 11.5 (10.3-12.6) 2001-2002 25.7 12.2 8.4 3.8 7.2 522 12.2 (11.0-13.4) 2003-2004 24.0 12.0 6.0 3.7 4.4 447 10.7 ( 9.7-11.8) 2005-2006 27.8 15.7 6.3 3.9 5.8 504 12.9 (11.7-14.1) 2007-2008 27.3 18.7 11.2 3.5 4.2 601 14.3 (13.1-15.4) 2009-2010 29.1 17.2 10.4 5.9 2.7 619 14.4 (13.2-15.5) 2011-2012 24.3 17.1 7.6 4.5 1.6 527 12.1 (11.1-13.1) 2013-2014 20.2 14.8 7.7 3.5 1.4 479 10.4 ( 9.5-11.4) 2015-2016 19.2 16.6 6.9 4.3 3.7 490 10.9 ( 9.9-11.9)

Note: Rates are expressed as number of women with high-grade abnormality detected by histology per 1,000 women screened and, for the aged 20-69 years, are age-standardised using the 2001 Australia Estimated Residents Population.

Cytology-histology correction

The correlation between the screening Pap test (cytology) result and the diagnostic biopsy (histology) result for women with an abnormal Pap test is an indication of the accuracy of the screening test. This correlation compared cytology ‘prediction’ and the most serious histology result within six months after the Pap test. The tabulation provides the distribution (as a percentage) of histology results for women within each cytology result category (Table 35 and Table 37).The ‘positive predictive value’ (PPV) is the probability that a high-grade abnormal Pap test is confirmed by histology to be high-grade abnormality or invasive cancer. The PPV is calculated as the proportion of cytology results of possible or definite high-grade abnormality that were confirmed on histology to be a high-grade abnormality or carcinoma. Correlation between screening cytology and diagnostic histology tests was assessed separately for squamous cell and endocervical cell abnormalities.

The PPV of Pap test screening for detecting high-grade squamous cell abnormalities in the NT was 70% for the total period 1997-2016, which is comparable to the national figure of 67.1% for 2014-2015 (Table 38). The PPV of cytology for detecting high-grade endocervical abnormalities in the NT was 39% for 1997-2016, which is well below the national figure of 72.7% for 2014-2015.


of 50

Table 34. Cervical screening: number and proportion of squamous cytology abnormalities being followed up by squamous histology within 6 months in screened women aged 20-69 years, by five-year period, NT 1997-2016

1997-2001 2002-2006 2007-2011 2012-2016

Cytology prediction % (counts) % (counts) % (counts) % (counts)

S2 Possible low-grade 15 (970 / 6449) 11 (560 / 4923) 15 (519 / 3355) 13 (646 / 4803) S3 Low-grade 38 (955 / 2486) 31 (804 / 2610) 20 (339 / 1705) 20 (368 / 1825) S4 Possible high-grade 63 (306 / 485) 64 (331 / 514) 65 (489 / 748) 64 (427 / 670) S5 High-grade 75 (1214 / 1616) 72 (871 / 1214) 77 (972 / 1267) 78 (819 / 1054) S6 High-grade plus 82 (46 / 56) 80 (36 / 45) 81 (34 / 42) 83 (43 / 52) S7 Squamous cell

carcinoma 90 (18 / 20) 78 (14 / 18) 83 (10 / 12) 75 (6 / 8)

Note: Counts are expressed as the number of histology tests over the number of cytology prediction in each category.

Table 35. Cervical screening: correlation between squamous cytology and the most serious squamous histology within 6 months in screened women aged 20-69 years, by five-year period, NT 1997-2016

Histology finding All

HS01 HS02 HS03 HS04 histology

Cytology predication Negative

Low-grade

High-grade

Squamous cell carcinoma

tests

n % n % n % n % n

1997-2001

S1 Negative 1,168 56.7 741 36.0 149 7.2 1 0.0 2,059 S2 Possible low-grade 317 33.5 421 44.5 208 22.0 0 0.0 946 S3 Low-grade 186 19.8 495 52.7 257 27.4 1 0.1 939 S4 Possible high-grade 71 23.7 91 30.3 136 45.3 2 0.7 300 S5 High-grade 87 7.2 183 15.2 919 76.4 14 1.2 1,203 S6 High-grade plus 2 4.3 2 4.3 34 73.9 8 17.4 46 S7 Squamous cell carcinoma 1 5.6 0 0.0 8 44.4 9 50.0 18

2002-2006

S1 Negative 789 52.1 526 34.8 198 13.1 0 0.0 1,513 S2 Possible low-grade 157 29.0 241 44.5 143 26.4 0 0.0 541 S3 Low-grade 141 18.0 404 51.5 240 30.6 0 0.0 785 S4 Possible high-grade 71 21.8 91 28.0 161 49.5 2 0.6 325 S5 High-grade 71 8.3 135 15.8 638 74.6 11 1.3 855 S6 High-grade plus 1 2.8 0 0.0 25 69.4 10 27.8 36 S7 Squamous cell carcinoma 2 14.3 0 0.0 2 14.3 10 71.4 14

2007-2011


2012-2016


Notes: n stands for number; % is the percentage of each histology category in the all histology tests by each cytology category.


of 50

Table 36. Cervical screening: number and proportion of endocervical cytology abnormalities being followed up by endocervical histology within 6 months in screened women aged 20-69 years, by five-year period, NT 1997-2016

1997-2001 2002-2006 2007-2011 2012-2016

Cytology prediction % (counts) % (counts) % (counts) % (counts)

E2 AECUS 19 (28 / 148) 17 (17 / 98) 46 (12 / 26) 44 (23 / 52)

E3 Possible high-grade 43 (29 / 67) 58 (32 / 55) 61 (30 / 49) 37 (19 / 51)

E4 Adenocarcinoma in situ 83 (19 / 23) 96 (22 / 23) 94 (16 / 17) 100 (13 / 13)

E6 Adenocarcinoma - (0 / 0) 67 (4 / 6) 100 (3 / 3) - (0 / 0) Notes: 1. Counts are expressed as the number of histology tests over the number of cytology prediction in each category. 2. AECUS stands for atypical endocervical cells of uncertain significance. 3. The category of E5 Adenocarcinoma in situ plus has no case the NTCSR.

Table 37 Cervical screening: correlation between endocervical cytology and the most serious endocervical histology within 6 months in screened women aged 20-69 years, by five-year period, NT 1997-2016

Histology finding All

HE01 HE03 HE04 histology Cytology predication Negative High-grade Adenocarcinoma tests

n % n % n % n

1997-2001 E1 Negative 4,491 99.6 18 0.4 1 0.0 4,510 E2 AECUS 25 96.2 1 3.8 0 0.0 26 E3 Possible high-grade 16 76.2 4 19.0 1 4.8 21 E4 Adenocarcinoma in situ 9 47.4 9 47.4 1 5.3 19 E6 Adenocarcinoma 0 - 0 - 0 - 0

2002-2006 E1 Negative 2,791 99.2 21 0.7 1 0.0 2,813 E2 AECUS 13 81.3 3 18.8 0 0.0 16 E3 Possible high-grade 15 62.5 9 37.5 0 0.0 24 E4 Adenocarcinoma in situ 4 23.5 13 76.5 0 0.0 17 E6 Adenocarcinoma 3 100.0 0 0.0 0 0.0 3

2007-2011 E1 Negative 2,608 99.5 13 0.5 1 0.0 2,622 E2 AECUS 9 90.0 1 10.0 0 0.0 10 E3 Possible high-grade 21 91.3 2 8.7 0 0.0 23 E4 Adenocarcinoma in situ 3 21.4 11 78.6 0 0.0 14 E6 Adenocarcinoma 1 100.0 0 0.0 0 0.0 1

2012-2016 E1 Negative 2,524 99.3 17 0.7 1 0.0 2,542 E2 AECUS 16 88.9 2 11.1 0 0.0 18 E3 Possible high-grade 14 100.0 0 0.0 0 0.0 14 E4 Adenocarcinoma in situ 4 30.8 9 69.2 0 0.0 13 E6 Adenocarcinoma 0 - 0 - 0 - 0

Notes: 1. n stands for number; % is the percentage of each histology category in the all histology tests by each cytology category. 2. AECUS stands for atypical endocervical cells of uncertain significance. 3. The category of E5 Adenocarcinoma in situ plus has no case. 4. The code of HE02 endocervical atypia is not used in the NTCSR.


of 50

Table 38 Cervical screening: positive predictive value (PPV) of high-grade cytology abnormalities and the most serious histology within 6 months in screened women aged 20-69 years, by five-year period, NT 1997-2016

Cytology prediction

Squamous high-grade

Endocervical high-grade

PPV (counts) PPV (counts)

1997-2001 70% (1097 / 1566) 33% (13 / 40) 2002-2006 67% (826 / 1238) 54% (22 / 41) 2007-2011 71% (1056 / 1495) 35% (13 / 37) 2012-2016 72% (924 / 1289) 33% (9 / 27)

1997-2016 70% (3903 / 5588) 39% (57 / 145) Note: Counts are expressed as the number of confirmed histology high-grade abnormalities over the number of cytology high-grade abnormalities in each type.

Incidence of cervical cancer in women

The cervical cancer incidence rate for NT non-Aboriginal women aged 20-69 years was similar to the total Australian rate, and both decreased considerably, between 1991 and 2005 (Figure 15). This decrease is attributable to the national cervical screening program that commenced in the early 1990s. For NT Aboriginal women, cervical cancer incidence was 50 per 100,000 women in 1991-1995, 150% higher than the NT non-Aboriginal rate (Table 39). Incidence decreased by 63% to 18.3 per 100,000 women in 2011-2015, but this remains 60% higher than the NT non-Aboriginal rate.

Table 39. Cervical cancer incidence: numbers and age-standardised rates in women aged 20-69, by Indigenous status and five-year period, NT 1991-2015


Cases Rate (95%CI) Cases Rate (95%CI) Aboriginal/Non-Aboriginal

1991-1995 20 50.0 (27.3-72.8) 33 20.1 (12.5-27.8) 2.5 1996-2000 19 35.1 (18.4-51.8) 29 14.5 (8.9-20.1) 2.4 2001-2005 12 20.1 (7.7-32.5) 30 12.5 (7.9-17.2) 1.6 2006-2010 20 25.4 (13.5-37.2) 32 12.4 (8.1-16.7) 2.0 2011-2015 16 18.3 (9.3-27.4) 31 11.1 (7.2-15.0) 1.6



of 50

Figure 15. Cervical cancer incidence: age-standardised rates in women aged 20-69, by Indigenous status and five-year period, NT 1991-2015 vs Australia




of 50

References

AIHW 2018a. BreastScreen Australia monitoring report 2018. Cancer series no. 112. Cat. no. CAN 116.

Canberra: AIHW.

AIHW 2018b. Cervical screening in Australia 2018. Cat. no. CAN 111. Canberra: AIHW.

AIHW 2019a. Cancer in Australia 2019. Cancer series no. 119. Cat. no. CAN 123. Canberra: AIHW.

AIHW 2019b. National Bowel Cancer Screening Program: monitoring report 2019. Cancer series no.

125. Cat. no. CAN 125. Canberra: AIHW.

Cancer Screening. 2019a. National Bowel Cancer Screening Program. [ONLINE] Available at:

http://www.cancerscreening.gov.au/internet/screening/publishing.nsf/Content/bowel-screening-1.

[Accessed 21 August 2019].

Cancer Screening. 2019b. National Cervical screening Program. [ONLINE] Available at:

http://www.cancerscreening.gov.au/internet/screening/publishing.nsf/Content/cervical-screening-1.

[Accessed 21 August 2019].

Condon JR, Zhang X, Dempsey K, Garling L, Guthridge S. Trends in cancer incidence and survival for

Aboriginal and non‐Aboriginal people in the Northern Territory. MJA 2016;205(10):454-8.

Department of Health 2018. Northern Territory Resident Population Estimates by Age, Sex, Indigenous Status and health districts (1971-2017). Innovation and Research Branch, updated on 16 May 2018.

NT Government. 2019a. BreastScreenNT. [ONLINE] Available at: https://nt.gov.au/wellbeing/cancer-

services/breastscreennt. [Accessed 21 August 2019].

NT Government. 2019b. Cervical screening. [ONLINE] Available at: https://nt.gov.au/wellbeing/health-

conditions-treatments/womens-health/cervical-screening. [Accessed 21 August 2019].

NT Government. 2019c. Northern Territory Cancer Registry (NTCR). [ONLINE] Available at:

https://health.nt.gov.au/professionals/health-gains/northern-territory-cancer-registry. [Accessed 21

August 2019].

http://www.cancerscreening.gov.au/internet/screening/publishing.nsf/Content/bowel-screening-1

http://www.cancerscreening.gov.au/internet/screening/publishing.nsf/Content/cervical-screening-1

https://nt.gov.au/wellbeing/cancer-services/breastscreennt

https://nt.gov.au/wellbeing/cancer-services/breastscreennt

https://health.nt.gov.au/professionals/health-gains/northern-territory-cancer-registry


of 50

Appendix. Map of Northern Territory Health Districts


of 50

List of tables

Table 1. Bowel cancer screening: number of returned screening tests and participation rate, by Indigenous status, NT 2007-2017 ........................................................................................................... 12 Table 2. Bowel cancer screening: number of positive results and positivity rate, by Indigenous status, NT 2007-2017 .............................................................................................................................................. 12 Table 3. Bowel cancer screening: number of follow-up colonoscopy and diagnostic assessment rate, by remoteness and Indigenous status, NT 2007-2017 ................................................................................ 13 Table 4. Bowel cancer screening: time between positive FOBT result and follow-up colonoscopy, by remoteness and Indigenous status, NT 2007-2017 ................................................................................ 13 Table 5. Bowel cancer screening: detection of advanced adenomas and confirmed cancer, by age group, NT 2007-2017 ........................................................................................................................................ 14 Table 6. Bowel cancer incidence: numbers and age-standardised rates in people aged 50-74, by Indigenous status and five-year period, NT 1991-2015 ........................................................................... 14 Table 7. NBCSP performance indicators for people aged 50-74 years, NT and Australia ....................... 15 Table 8. Breast cancer screening: number of women screened, by Indigenous status, age group and two-year period, NT 1998-2017 .............................................................................................................. 18 Table 9. Breast cancer screening: participation rate, by Indigenous status and age group, NT 1998-2017 ............................................................................................................................................................... 19 Table 10. Breast cancer screening: participation of women aged 50-69, by Indigenous status and health district, NT 2016-2017 ............................................................................................................................ 19 Table 11. Breast cancer screening: number and proportion of screens using fixed or mobile service, by Indigenous status and two-year period, NT 1998-2017 ........................................................................... 20 Table 12. Breast cancer screening: numbers of screens and recalls for assessment, by Indigenous status and two-year period, NT 1998-2017 ............................................................................................. 22 Table 13. Breast cancer screening: numbers of screens and recalls for assessment, by health district, NT 2013-2017 ........................................................................................................................................ 22 Table 14. Breast cancer screening: invasive breast cancer detection in women aged 50-69, by Indigenous status and screening round, NT 1998-2017 .......................................................................... 23 Table 15. Breast cancer screening: DCIS detection in women aged 50-69, by Indigenous status and screening round, NT 1998-2017 ............................................................................................................. 23 Table 16. Breast cancer screening: duration from screening visit to assessment and from assessment to treatment, by Indigenous status, NT 1998-2017 ..................................................................................... 23 Table 17. Breast cancer incidence: numbers and age-standardised rates in women aged 50-69, by Indigenous status and five-year period, NT 1991-2015 ........................................................................... 24 Table 18. Cevical screening: number of women screened aged 20-69 years, by recorded Indigenous status, NT 1997-2016 ............................................................................................................................. 26 Table 19. Cevical screening: women at their first screening, by recorded Indigenous status, NT 1997-2016 ....................................................................................................................................................... 26 Table 20. Cevical screening: women at their first screening, by recorded Indigenous status and health district, NT 2012-2016 ............................................................................................................................ 27 Table 21. Cervical screening: women screened, by Indigenous status and age group, NT 1997-2016 ... 29 Table 22. Cervical screening: age-specific and age-standardised participation rates of women aged 20-69 years, by Indigenous status, NT 1997-2016....................................................................................... 30 Table 23. Cervical screening: effect of possible missing Aboriginal participants on participation of women aged 20-69 years, by Indigenous status, NT 2011-2016 ......................................................................... 30 Table 24. Cervical screening: number and age-standardised participation rate of women aged 20-69 years, by health district, NT 2015-2016 .................................................................................................. 31 Table 25. Cervical screening: proportion of early rescreening in screened women aged 20-69 years, by number of repeats and health district, NT, index screenings of 2014-2015 ............................................. 33 Table 26. Cervical screening: age-specific prevalence of abnormal cytology results in screened women aged 20-69 years, by two-year period, NT 1997-2016 ............................................................................ 34 Table 27. Cervical screening: age-standardised prevalence of cytology result category in screened women aged 20-69 years, by two-year period, NT 2015-2016 ................................................................ 35 Table 28. Cervical screening: age-standardised prevalence of cytology high-grade abnormality in screened women aged 20-69 years, by two-year period and Indigenous status, NT 1997-2016 ............. 36


of 50

Table 29. Cervical screening: age-standardised prevalence of cytology result category in screened women aged 20-69 years, by health district, NT 2012-2016 ................................................................... 36 Table 30. Cervical screening: histology test as proportion (%) of cytology tests in screened women aged 20-69 years, by two-year period and age group, NT 1997-2016 ............................................................. 36 Table 31. Cervical screening: age-specific prevalence of histology result category in histology-tested women aged 20-69 years, by two-year period, NT 1997-2016 ................................................................ 37 Table 32. Cervical screening: age-standardised prevalence of histology result category in histology-tested women aged 20-69 years, by two-year period, NT 1997-2016 ..................................................... 37 Table 33. Cervical screening: age-specific and age-standardised high-grade abnormality detection rates in screened women aged 20-69 years, by Indigenous status and two-year period, NT 1997-2016 ......... 40 Table 34. Cervical screening: number and proportion of squamous cytology abnormalities being followed up by squamous histology within 6 months in screened women aged 20-69 years, by five-year period, NT 1997-2016 ........................................................................................................................................ 41 Table 35. Cervical screening: correlation between squamous cytology and the most serious squamous histology within 6 months in screened women aged 20-69 years, by five-year period, NT 1997-2016 .... 41 Table 36. Cervical screening: number and proportion of endocervical cytology abnormalities being followed up by endocervical histology within 6 months in screened women aged 20-69 years, by five-year period, NT 1997-2016 ..................................................................................................................... 42 Table 37 Cervical screening: correlation between endocervical cytology and the most serious endocervical histology within 6 months in screened women aged 20-69 years, by five-year period, NT 1997-2016 .............................................................................................................................................. 42 Table 38 Cervical screening: positive predictive value (PPV) of high-grade cytology abnormalities and the most serious histology within 6 months in screened women aged 20-69 years, by five-year period, NT 1997-2016 ........................................................................................................................................ 43 Table 39. Cervical cancer incidence: numbers and age-standardised rates in women aged 20-69, by Indigenous status and five-year period, NT 1991-2015 ........................................................................... 43


of 50

List of figures

Figure 1. Bowel cancer incidence: age-standardised rates in people aged 50-74, by Indigenous status and five-year period, NT 1991-2015 vs Australia 2016 ........................................................................... 15 Figure 2. Breast cancer screening: participation rate of women aged 50-69, by Indigenous status, NT 1998-2017 .............................................................................................................................................. 17 Figure 3. Breast cancer screening: number of screens using fixed or mobile service, by Indigenous status and two-year period, NT 1998-2017 ............................................................................................. 21 Figure 4. Breast cancer screening: proportion (%) of screens using mobile service, by Indigenous status and two-year period, NT 1998-2017 ....................................................................................................... 21 Figure 5. Breast cancer incidence: age-standardised rates in women aged 50-69, by Indigenous status and five-year period, NT 1991-2015 vs Australia .................................................................................... 24 Figure 6. Cevical screening: proportion (%) of women at their first screening, by recorded Indigenous status, NT 1997-2016 ............................................................................................................................. 27 Figure 7. Cevical screening: age-standardised participation rate of women aged 20-69 years, by Indigenous status, NT 1997-2016 ........................................................................................................... 28 Figure 8. Cervical screening: age-specific participation rate of women aged 20-69 years, NT and Australia 2015-2016 ............................................................................................................................... 31 Figure 9. Cervical screening: age-standardised participation rate of women aged 20-69 years, by health district, NT 2015-2016 ............................................................................................................................ 32 Figure 10. Cervical screening: proportion (%) of early rescreening in screened women aged 20-69 years, by year of index screening and Indigenous status, NT 1997-2015 .......................................................... 33 Figure 11. Cervical screening: age-specific prevalence of abnormal cytology results in screened women aged 20-69 years, NT 2015-2016 ........................................................................................................... 34 Figure 12. Cervical screening: age-standardised prevalence of cytology high-grade abnormality in screened women aged 20-69 years, by two-year period and Indigenous status, NT 1997-2016 ............. 35 Figure 13. Cervical screening: age-standardised prevalence of abnormal histology results in histology-tested women aged 20-69 years, by two-year period, NT 1997-2016 ..................................................... 38 Figure 14. Cervical screening: age-standardised high-grade abnormality detection rates in screened women aged 20-69 years, by Indigenous status and two-year period, NT 1997-2016 ............................ 39 Figure 15. Cervical cancer incidence: age-standardised rates in women aged 20-69, by Indigenous status and five-year period, NT 1991-2015 vs Australia .......................................................................... 44


of 50

Selected Innovation and Research Branch publications on cancer and cancer screening

Departmental publications

Condon JR & Zhao Y. Northern Territory Cancer Register Data Collection, analysis and reporting

procedures. Darwin: Department of Health and Community Services, 2004.

Condon JR, Zhao Y, Armstrong BK & Barnes T. Northern Territory Cancer Register Data Quality 1981–

2001. Darwin: Department of Health and Community Services, 2004.

Zhao Y, Condon JR & Garling LS. Cancer Incidence and Mortality Northern Territory 1991–2001.

Darwin: Department of Health and Community Services, 2004.

Condon JR, Lee H & Garling LS. Cancer survival, Northern Territory 1991-2001. Darwin: Department of

Health and Community Services, 2006.

Condon JR, Zhang X, Li SQ & Garling LS. Northern Territory Cancer Incidence and Mortality by Region,

1991-2003. Department of Health and Community Services, 2007.

Zhang X, Condon J, Dempsey K & Garling L. Cancer incidence and mortality, Northern Territory 1991–

2005. Department of Health and Families, Darwin, 2008.

Zhang X, Condon J, Douglas F, Bates D, Guthridge S, Garling L, Enciso G, Chondur R. Women’s

cancers and cancer screening in the Northern Territory. Department of Health, Darwin, 2012.

Journal articles

Condon JR, Barnes T, Cunningham J, Armstrong BK. Long-term trends in cancer mortality for

Indigenous Australians in the Northern Territory. Med J Aust. 2004;180(10):504-7.

Condon JR, Barnes T, Armstrong BK, Selva-Nayagam S, Elwood JM. Stage at diagnosis and cancer

survival for Indigenous Australians in the Northern Territory. Med J Aust. 2005;182(6):277-80.

Condon JR, Armstrong BK, Barnes T, Zhao Y. Cancer incidence and survival for indigenous Australians

in the Northern Territory. Aust N Z J Public Health. 2005;29(2):123-8.

Condon JR, Cunningham J, Barnes T, Armstrong BK, Selva-Nayagam S. Cancer diagnosis and

treatment in the Northern Territory: assessing health service performance for indigenous Australians.

Intern Med J. 2006;36(8):498-505.

Binns PL, Condon JR. Participation in cervical screening by Indigenous women in the Northern Territory:

a longitudinal study. Med J Aust. 2006;185(9):490-4.

Cunningham J, Rumbold AR, Zhang X, Condon JR. Incidence, aetiology, and outcomes of cancer in

Indigenous peoples in Australia. Lancet Oncol. 2008;9(6):585-95.

Zhang X, Condon JR, Rumbold AR, Cunningham J, Roder DM. Estimating cancer incidence in

Indigenous Australians. Aust N Z J Public Health 2011;35(5):477-85.

Condon JR, Zhang X, Baade P, Griffiths K, Cunningham J, Roder DM, Coory M, Jelfs PL, Threlfall T.

Cancer survival for Aboriginal and Torres Strait Islander Australians: a national study of survival rates

and excess mortality. Population health metrics. 2014 Jan 31;12(1):1.

Condon JR, Zhang X, Baade P, Dempsey D, Garling L, Guthridge S. Trends in cancer incidence and

survival for Indigenous and non-Indigenous people in the Northern Territory. MJA 2016:205(10):454-8.

cancer screening in the nt - doh digital library: home · breast cancer breast cancer is the most...

Documents