Cancer Screening in Asymptomatic Adults
A 52 year old asymptomatic man attends for a preventive health visit. He has no family history of cancer, has never smoked, and has a normal physical examination. He asks which cancers he should be routinely screened for in the absence of symptoms or specific risk factors. Which of the following cancers warrants routine screening in him?
- A.Skin cancer
- B.Colorectal cancerCorrect
- C.Thyroid cancer
- D.Bladder cancer
Explanation
Colorectal cancer screening is recommended for all average risk adults from age 45 to 75 years, making it the correct choice for this asymptomatic 52 year old man. Acceptable strategies include annual faecal immunochemical testing, faecal immunochemical DNA testing every 1 to 3 years, computed tomography colonography every 5 years, or colonoscopy every 10 years, and the best test is largely the one the patient will actually complete. Screening works because the adenoma to carcinoma sequence provides a long detectable preclinical phase and because removing adenomas prevents cancer rather than only detecting it early. For adults aged 76 to 85 years, screening is individualised according to comorbidity, prior screening and life expectancy. Whole body skin examination for skin cancer in asymptomatic adults has insufficient evidence of benefit, although patients at high risk merit surveillance. Thyroid cancer screening by neck palpation or ultrasound is recommended against, because it detects indolent papillary microcarcinomas and drives overtreatment with surgery and lifelong thyroxine, as the South Korean experience showed. Bladder cancer screening in asymptomatic adults also lacks evidence of benefit. This man is a never smoker and therefore does not meet lung cancer screening criteria.
Why each option
- A.
- Routine whole body skin examination in asymptomatic adults has insufficient evidence of net benefit.
- B.
- Correct. Average risk adults from 45 to 75 years should be screened for colorectal cancer.
- C.
- Thyroid cancer screening is recommended against because it causes overdiagnosis and overtreatment of indolent tumours.
- D.
- Bladder cancer screening in asymptomatic adults is not supported by evidence of mortality benefit.
Reference: US Preventive Services Task Force. Screening for Colorectal Cancer. JAMA. 2021;325(19):1965-1977
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