For the general population considered to be at an average risk of getting colon cancer, it is generally recommended that screening for colon cancer begin at age 50 (whether through fecal occult blood testing, flexible sigmoidoscopy or colonoscopy
). For patients that have a strong family history of colon cancer then your doctor
may choose to begin screening at an earlier age. This is especially the case if more than one first-degree relative has been diagnosed with colon cancer and there is high suspicion of an inheritable syndrome that predisposes to colon cancer. Screening at an earlier age is also recommended if a first-degree relative has been diagnosed at a relatively young age; in this case screening should start 10 years earlier than the age at which this relative was diagnosed or age 50, whichever comes first. The other population that should start colon cancer screening
earlier than the general population includes patients with a history of inflammatory bowel disease.
For the general average-risk patient, the recommendation on when to repeat screening depends on the type of modality used to screen and the results of any prior colonoscopy. If pre-cancerous polyps are found on the initial screen, then your doctor may need to repeat your next colonoscopy in 3-5 years. If no polyps are found on colonoscopy, then generally a repeat colonoscopy is recommended in 10 years.