Which cancer screenings are worthwhile, and from what age?
Colorectal cancer screening from age 50 and mammography from age 40 have the best evidence base for the average person; lung cancer screening is only relevant if you have a heavy smoking history. Other screenings are only worthwhile in the presence of specific risk factors or inherited conditions.
Colorectal cancer screening has the strongest evidence base of all cancer screenings. Between the ages of 50 and 75, the net benefit is substantial and has been established with high certainty. Between 45 and 49, there is still a moderate benefit. Above the age of 75, the choice depends on your personal health and life expectancy. You can choose between an annual stool test or a colonoscopy at longer intervals; discuss your preference with your doctor.
Mammography for breast cancer is recommended for women aged 40 to 74. Screening every two years is the common standard; for those at elevated risk, annual screening or an MRI scan may be more appropriate, sometimes starting at a younger age. The benefit is moderate and found fairly consistently across international guidelines. For women aged 75 and older, the evidence is too limited to make a clear recommendation.
Lung cancer screening with a low-dose CT scan is worthwhile, but only for a specific group: smokers (or former smokers who quit within the past fifteen years) aged 50 and older with a smoking history of at least twenty pack-years. Twenty pack-years means, for example, twenty years of one pack per day, or ten years of two packs per day. For people without a heavy smoking history, there is no reason to pursue this screening.
Anal cancer screening is intended for specific high-risk groups. Men who have sex with men and transgender women with HIV start at age 35. Other people with HIV, or MSM and transgender women without HIV, start at age 45. Organ transplant patients begin ten years after the transplant. This is not a screening for the general population.
Pancreatic cancer screening is only worthwhile if you have a strong family history or an inherited condition that increases the risk, such as Peutz-Jeghers syndrome or hereditary pancreatitis. In that case, annual monitoring is recommended, starting at age 50 or ten years earlier than the youngest affected family member. With certain genetic syndromes, screening may begin as early as age 35 to 40. For the rest of the population, there is no recommendation.
Screening for uterine cancer in women without symptoms has no proven benefit. Women over the age of 65 are advised to pay close attention to symptoms such as bleeding after menopause and to consult a doctor promptly if this occurs.
Claims are based on USPSTF recommendations, a systematic review of 23 international guidelines, and specific guidelines from the International Anal Neoplasia Society and gastroenterological experts. Strength of evidence varies by screening type: strong for colorectal cancer, moderate for breast cancer and lung cancer, limited for pancreatic cancer and anal cancer in high-risk groups, and insufficient for uterine cancer in asymptomatic women.