Colonoscopy

The doctor uses a thin, flexible, lighted tube to check for polyps or cancer inside the rectum and the entire colon. During the test, the doctor can find and remove most polyps and some cancers. Colonoscopy also is used as a follow-up test if anything unusual is found during one of the other screening tests.

How often: Every 10 years (for people who do not have an increased risk of colorectal cancer).

Source: https://www.cdc.gov/cancer/colorectal/basic_info/screening