Download - Screening and Early Diagnosis in Oncology
Screening and Early
Diagnosis in Oncology
Başak Oyan-Uluç, MDYeditepe University Hospital
Department of Medical Oncology
Prevention
PrimaryElimination of
risk factor• Cessation of
smoking• Colonoscopy• Vaccination• Lifestyle
modifications
Onset of disease Clinical diagnosis
Asymptomatic Clinical courseHealthy
SecondaryEarly diagnosis
and treatment• Colonoscopy
• Mamography
• Pap smear
TertiaryReducing
complications (rehabilitation)
Cancer Screening
• Cancer screening: Early detection of asymptomatic or unrecognized disease by the application of inexpensive tests or examinations in a large number of people.
• Main objective: To reduce morbidity and mortality from a particular cancer among people screened.
• Screening procedure itself– Not diagnostic– Detects people with cancer risk – Positive or suspicious findings must be evaluated further to
determine diagnosis and appropriate treatment.
Screening vs. Diagnosis
Screening Diagnosis
Applied to asymptomatic groups
Applied to symptomatic individuals
Lower cost per test Higher cost, all necessary tests applied to identify disease
Lower yield per test Increased probability of case detection
Lower adverse consequences of error
Failure to identify true positive can delay treatment, worsen prognosis
Ideal screening program
Patient features• High impact: Morbidity,
mortality, economy• High incidance and high
prevelance• Predictable corse and biology • High prevelance of preclinic
phase• Effective treatment exists
Requirements of screening test
• Diagnosing disease at preclinical phase
• Acceptable sensitivity and specificy
• Acceptable to people• Simple anf cheap• Safe
Quality of primary or secondary prevention (Cheap, effective, safe)
Benefits of Screening
• Improved prognosis for those with early-detected cancers
• Less radical treatment
• Reassurance for those with negative test results
• Reduction of treatment costs
Hazards of screening
• The potential for overdiagnosis (Labelling phenomenon)
• The potential carcinogenic effects of screening (i.e. Radiation risk with mammography)
• The economic consequences of false-negatives
Cervical Cancer-Pap Smear
1. Long preinvasive period
2. Increased morbidity and mortality in invasive period
3. Treatable if early diagnosis
4. PAP smear: Sensitive, low cost, easy to apply, safe
• Although there are more than 100 different cancers, most of them lack proven screening interventions
• Cancers that have widely accepted screening interventions
• Breast• Cervix• Colorectal• Prostate ?
• Hepatocellular cancer in patients with risk factor• Lung cancer in people with defined risk factors
Cancers suitable for screening
Breast Cancer Screening
• Most common cancer in females
• Average risk
• Increased risk– Prior thoracic RT (eg. Mantle)– Women who have a lifetime risk of >%20– Strong family history of genetic predisposition– LCIS/atypical hyperplasia– Prior history of breast cancer
Breast Cancer ScreeningAverage risk women
Widely accepted techniques for breast cancer screening includes– Brest self-examination: Monthly after age 20– Clinical breast examination:
• Age 20-39: Every 1-3 years• Every year after age 40
– Mamography: Every year after age 40• Decrease mortality by 20-30%
Cervical Cancer Screening
• Second most common cancer in females worldwide particularly in the underdeveloped regions
• The incidence has declined in many countries due to the improved standard of living throughout the world
Cervical Cancer Screening
• Pap test: Introduced in 1930s by Dr. Papanicolaou
• Screening should begin at age 21
• Discontinuation of screening– At age 65-70, if 3 negative tests and no abnormal tests in
preceeding 10 years
• Screening not discontinued in– In-uterine DES exposure
– Personal history of servical cancer
– Immune insuffiency (eg. HIV)
– HPV DNA (+)
Sawaya G. N Engl J Med 2009;10.1056/NEJMp0911380
Cervical Cytologic Screening Guidelines from the American College of Obstetricians and Gynecologists, 2009
Colorectal Cancer Screening
• Causes morbidity and mortality in both men and women
• Second leading cause of death due to cancer
• The natural history of colon cancer with relatively long time from biologic onset to development of carcinoma makes it a good candidate for screening
Risk groups for screening• Average risk
– Age ≥ 50 y– No inflammatoy bowel disease– No history of adenoma or colorectal cancer– Negative family history
• Increased risk– Personal history of
• Adenoma/sessile serrated polyp• Inflammatoy bowel disease• Colorectal cancer
– Positive family history
• High risk syndromes– Lynch syndrome/Hereditary nonpolyposis colorectal cancer (HNPCC)– Polyposis syndromes (familial adenomatous polyposis, Peutz-
Jeggers syndrome, Juvenile polyposis syndrome, hyperplastic polyposis syndrome)
Screening tests for colorectal cancerAverage risk
Starts at age 50
1. Colonoscopy every 10 years • preferred if available• For every 1% increase in complete colonoscopy rate, the hazard of
death decreased by 3%.
2. Annual FOBT+Flexible sigmoidoscopy every 5 years
Annual Fecal occult blood test (FOBT)• Testing of stool for occult blood to detect colorectal cancer at an early
stage• Variation is observed in estimates of the sensitivity but its lower cost and
increased specificity to detect right-isded colonic lesions make it a good screening test
Flexible sigmoidoscopy every 5 years • In contrast to FOBT, has a high sensitivity and specificity • Involves the use of a 60 cm flexible sigmoidoscope• Detects left sided lesions
Prostate Cancer Screening
• Most commonly diagnosed cancer among men and is the second leading cause of male cancer deaths
• Two main screening modalities• Serum prostate specific antigen (PSA) • Digital rectal examination (DRE)
Prostate Cancer Screening• Benefit of screening is controversial
• Prostate cancer is common and potentially lethal; however, more patients die with, rather than from, the disease.
• Incidence: 1/6 Mortality: 1/30
• Screening detects more cases of organ-confined disease, but there is no proof that this detection saves lives.
• In more instances, prostate cancer is not the cause of elevated PSA level.
NEJM 2009; 360:1310NEJM 2009; 360:1320
Prostate Cancer Screening
• Localized treatment of prostate cancer is effective but is associated with complications than can include impotence and incontinence (~ 50%).
• It is likely that prostate cancer screening using the PSA level is beneficial in a subset of men; however, the characteristics of the subset have not been defined.
Prostate Cancer Screening
• Discuss benefit and harms of screening with the patient
• In men with a life expectancy of >10 years, start annual screening at age 40y with: – PSA – Digital rectal examination
• In last years it is recommended to offer a baseline DRE and PSA at age 40 y.
Prostate Cancer Screening
• DRE• Most widely used and oldest technique for
detection of prostate cancer• Wide ranges of sensitivity (33%-69%) and
specificity (49%-97%)
• Serum PSA level• Allows earlier detection of prostate cancer• Normal PSA values are found in 1/3 of localized tumors
(false negative)• Often elevated in men with noncancerous conditions
such as benign prostatic hyperplasia (false positive)
Prostate Cancer Screening
• NCCN recommendation– DRE yearly starting at age 40– PSA yearly starting at age 40
Lung Cancer Screening
Target population:•Age: 55-74 years +•Smoked ≥ 30 pack/year +•Continue to smoke or have quitted smoking within 15 years
Screeninig method: Low dose thorax CT
Hepatocellular Carcinoma
Cirrhosis• Hepatitis B, C• Alcohol• Genetic hemocromatosis• Non-alcoholic
steatohepatitis• Autoimmune hepatitis• Primary biliary cirrhosis
No cirrhosis• Hepatitis B carrier• Non-alcoholic
steatohepatitis
Ultrasonography
Alpha-feto protein (AFP)
Every 6-12 months
Diagnosis rate: %92
False (+): %7.5
People not to be screened
• Life expectancy <5 years
• People who do not wish to undergo additional diagnostic tests or who do not want any treatment
Future of Screening
• Compliance: Encourage people to adhere the proven cancer screening modalities
• New and better methods: With the discovery of cancer susceptibility genes (e.g. BRCA-1 susceptibility gene for breast cancer) lifetime risk for an individual to develop a specific cancer could be estimated.