Making the Diagnosis
The colonoscopy is the primary screening method used for people at high risk of developing colon cancer. An endoscope, a flexible fiber-optic tube, is inserted into the colon to look for bleeding, polyps, or tumors. The procedure is not painful, though it can be a little uncomfortable.
The doctor may also feel inside the rectum and lower colon with a gloved finger. Sometimes you'll be asked to provide a stool sample to look for hidden blood. If any growths are found, the doctor will take a tissue sample (biopsy).
Some doctors screen everyone over 50 every year or two. Others concentrate their efforts on high-risk people such as people with a family history of colorectal cancer, people with Crohn's disease or ulcers, or people who already have polyps.