Prostate cancer in Australia – what do the numbers tell us?

7 August 2020

The Australian Institute of Health and Welfare (AIHW) has just released the latest figures on

prostate cancer incidence, mortality, and survival in Australia.

The trends over time are different to the trends we see for many other types of cancer, including a

decreasing number of diagnoses since 2009, when cases peaked in Australia. In that year, 22,146

cases were diagnosed, compared to 16,741 cases expected to be diagnosed this year. With an

ageing and increasing population, we might ordinarily expect to see the number of men diagnosed

increase, but this has not been the case.

Why?

According to the AIHW:

“Prostate-specific antigen (PSA) testing and associated changes in guidelines can affect the

number of new cases of prostate cancer. PSA testing was introduced in 1987 and is thought to

have contributed to the peak in incidence in the 1990s. The PSA threshold at which males were

referred for a prostate biopsy was lowered in 2002 and might have contributed to the peak

incidence during the mid to late 2000s (Smith et al. 2008).”

That is, testing protocols may have contributed to over-diagnosis and over-treatment in the mid to

late 2000s, whereas in recent years a revised set of PSA Test Guidelines (2016) has helped to

address this concern, in parallel with the availability of new treatment protocols, such as Active

Surveillance and Watchful Waiting, which reduce the potential risk of over-treating prostate

cancers that pose minimal risk.

Numbers versus rates

There are two standard measures for understanding big-picture cancer trends, these are the

number count of people diagnosed, and the rate, expressed as the number diagnosed per 100,000

people. Due to Australia’s ageing and increasing population, and the link between ageing and

cancer risk, it is common to see the number of Australians diagnosed with cancer increase, while

overall rates trend downwards, thanks to better prevention strategies for many cancer types, and

improved methods of detecting more common cancers in their earliest stages and effectively

treating them.

Expressed in charts, this is what the trends look like for prostate cancer incidence and mortality in

Australia for the period from 1982 to 2019:

Source: https://ncci.canceraustralia.gov.au/cancer-types/prostate-cancer

The improved mortality rate is a key measure of success and is reflected in increasingly higher

rates of survival over time:

Source: https://www.aihw.gov.au/reports/cancer/cancer-data-in-australia/contents/cancer-survival-

data-visualisation

In 1987–1991, on average, 60% of males (all ages) diagnosed with prostate cancer survived five

years after diagnosis, whereas in 2012–2016, on average, 95.4% of males (all ages) diagnosed

with prostate cancer survived five years after diagnosis.

This is tremendous progress, thanks to rapid advances in research and treatment.

According to the government agency, Cancer Australia:

Survival from cancer can be influenced by various factors including demographic characteristics,

tumour type, stage of the cancer at diagnosis, other prognostic indicators and availability of

treatment. Cancer survival refers to the proportion of patients expected to survive their cancer at a

specified point subsequent to the diagnosis of cancer, or from some designated point after

diagnosis (conditional survival). It is commonly presented as the probability of surviving their

cancer at a specified time after diagnosis, e.g. 5-year or 10-year survival.

The measure ‘5-year relative survival at diagnosis’ is defined as the ratio of the proportion of

people who are alive for 5 years after their diagnosis of cancer (observed survival), to the

proportion of people in the general population alive over the same time interval (expected survival).

Those in the general population are normally matched for age, sex and calendar year to those with

cancer. Observed survival is calculated for Australia, using data from population-based cancer

registries. Expected survival is calculated from life tables for the entire Australian population.

Survival rates for prostate cancer therefore vary depending on the stage of cancer at diagnosis,

the patient’s age, and the characteristics of the cancer itself, among other things.

Incidence

Prostate cancer is the most commonly diagnosed cancer in Australian men. Estimates suggest

that 16,741 Australian men will be diagnosed this year (https://canceraustralia.gov.au/affected-

cancer/cancer-types/prostate-cancer/statistics).

Estimated most common cancers diagnosed among males, 2020:

The rate of age-standardised incidence in 2016 was 141 cases per 100,000 males. This is

expected to decrease to 110 cases per 100,000 males in 2020.

Evidence shows that incidence rates for prostate cancer increase with age, and are highest among

the age group 70-74, decreasing thereafter.

That is, a male’s chance of being diagnosed with prostate cancer increases with his age.

Of the 16,741 Australian males expected to be diagnosed with prostate cancer this year, 465 (3%)

will be under 49 years of age, 5587 (33%) will be 50-64 years of age and 11,144 (67%) will be over

the age of 65.

Mortality

Prostate cancer is the second most common cause of cancer-related deaths in Australian males

after lung cancer. Of concern, estimates suggest that 3152 men will die from prostate cancer in

2020. The charts below are from the government agency Cancer Australia.

The rate of age-standardised mortality in 2018 was 24 deaths per 100,000 males. This is

expected to decrease slightly to 21 deaths per 100,000 males in 2020.

How does cancer stage influence survival?

Cancer stage refers to the extent of spread of cancer – the higher the number between I and IV,

the further the cancer has spread. In Australia, five-year relative survival for prostate cancer

diagnosed at Stage I is 100%. The survival rate for Stage 4 cancers is just 36.4%.

These rates highlight the importance of detecting prostate cancer at its earliest stages in order to

improve survival outcomes. Yet only 36% of prostate cancers are detected at Stage I in Australia,

46% are detected at Stage II, 11% are detected at Stage III, 4% are detected at Stage IV, and in

about 3% of cases the stage at diagnosis is unknown.

Demographic disparities

Those in marginalised groups commonly experience poorer outcomes when it comes to cancer

survival. This is true for prostate cancer, and in some instances the gap has widened over recent

years, meaning that advances in research and treatment have not been shared equitably across

the population. For Australian males affected by prostate cancer, evidence suggests those in

regional and rural areas, and those who live in areas of relative socio-economic disadvantage,

experience higher rates of mortality and lower rates of survival.

The mortality rate for Australian males who reside in regional and rural areas is 24% higher – at a

rate of 56.9 per 100,000 compared to 45.8 per 100,000 for those in urban areas (2007). Likewise,

regional and rural males had a five-year relative survival rate of 88% compared to a survival rate of

91% for males from urban areas over the same time period (2000-2004). You’ll find that data here:

https://www.mja.com.au/journal/2011/194/6/urban-rural-differences-prostate-cancer-outcomes-

australia-what-has-changed.

Among Indigenous Australians, incidence and mortality rates are lower than rates for non-

Indigenous Australians, due to a range of factors associated with overall health status and life

expectancy, but in spite of this, Aboriginal and Torres Strait Islander men who are diagnosed with

prostate cancer still experience comparatively poor survival outcomes. For the period from 2007 to

2014, these men had an 86% chance, on average, of living for five years after their diagnosis,

compared to a 92% survival rate for non-Indigenous Australians.

Family history

Awareness of your family history of prostate cancer is key to early diagnosis and survival of the

disease:

• If your father or brother have ever been diagnosed with prostate cancer, you have twice the

average risk of developing the disease.

• If you have two or more close male relatives who have been diagnosed, your lifetime risk of

developing prostate cancer increases five-fold.

• Your risk also increases if you have a strong family history of breast or ovarian cancer,

especially if a BRCA1 or 2 gene mutation was involved.

To find out more, visit our website: https://pcfa.org.au/awareness/know-your-family-history/.

Prevalence

Prevalence refers to the number of Australian men alive today following a diagnosis of prostate

cancer over any given data collection period, with the national data set containing records from

1982 onwards.

According to Cancer Australia, at the end of 2015, there were 18,650 males living who had

been diagnosed with prostate cancer that year, 89,703 males living who had been diagnosed

with prostate cancer in the previous 5 years (from 2011 to 2015) and 220,943 males living who

had been diagnosed with prostate cancer in the previous 34 years (from 1982 to 2015).

By 2040 it is predicted there will be 372,000 men living with or beyond prostate cancer in Australia,

representing a 68% increase and the greatest number of men or women diagnosed with any single

cancer.

How can we use this knowledge to reduce the burden of prostate cancer?

Understanding prostate cancer incidence, mortality, and survival is key to reducing the burden of

cancer. The data provides a foundation for estimating improved or reduced survival from clinical

trials and other medical and scientific studies and allows policy makers and practitioners to tailor

treatments and strategies for different groups, based on the risks we can identify from analysing

statistical trends.

It also allows us to monitor our rate of progress against set targets. One of Prostate Cancer

Foundation of Australia’s key targets is to significantly increase the number of Australian males

who are diagnosed at Stage I of the disease, so that we can improve survival prospects and

eliminate avoidable deaths. At the individual level, it helps us to target our messaging to men in at

risks groups, based on the knowledge that men will be at an increased risk as they age and if they

have a family history.

Reach out for support via 1800 22 00 99 or make a donation today via https://pcfa.org.au/donate/.