When should I have a colonoscopy?

You should have a colonoscopy if you have symptoms or signs that suggest the presence of cancer or polyps, if the result of a screening test is positive, or if you are at high risk for colon cancer. High-risk patients include people with a first-degree relative with colon cancer diagnosed before the age of 60. In this group screening should start at age 40 or 10 years before the age that their parent, sibling or child was diagnosed.