Colorectal cancer screening: why age 45 matters

Colorectal cancer can develop from polyps before symptoms appear. For adults at average risk, the U.S. Preventive Services Task Force recommends screening from age 45 through 75. From 76 through 85, the choice depends on health, screening history, and personal preferences.

Options include a fecal immunochemical test (FIT) each year, stool DNA-FIT tests such as Cologuard every 1 to 3 years, or colonoscopy every 10 years when results are normal. Any abnormal stool test needs a follow-up colonoscopy to complete screening. Each option has different benefits and limitations, so discuss which approach fits your health history and preferences.

Shield is an FDA-approved blood test for colorectal cancer screening in adults 45 and older at average risk. It can miss early cancers and most precancerous lesions: FDA patient information reports that it did not detect 87% of precancerous lesions in the study. A negative result does not guarantee cancer is absent, and a positive result needs colonoscopy. Shield is not a substitute for diagnostic colonoscopy or high-risk surveillance.

People with a family history of colorectal cancer or polyps, inflammatory bowel disease, or certain inherited conditions may need a different screening plan. Blood in the stool or a persistent change in bowel habits calls for medical evaluation rather than waiting for routine screening. If you are due, bring your prior test history to a primary care visit to discuss next steps.