Diagnosis

Screening tests play a key role in detecting polyps before they become cancerous. These tests can also help find colorectal cancer in its early stages, when you have a good chance of recovery.

Screening methods include:

  • Colonoscopy, the most sensitive test for colorectal polyps and cancer. If polyps are found, your doctor may remove them immediately or take tissue samples (biopsies) for analysis.
  • Virtual colonoscopy (CT colonography), a minimally invasive test that uses a CT scan to view your colon. Virtual colonoscopy requires the same bowel preparation as a colonoscopy. If a polyp is found, you'll need a colonoscopy to have it removed.
  • Flexible sigmoidoscopy, in which a slender, lighted tube is inserted in your rectum to examine it and the last third of your colon (sigmoid) and rectum. If a polyp is found, you'll need a colonoscopy to have it removed.
  • Stool-based tests. This type of test works by checking for the presence of blood in the stool or assessing your stool DNA. If your stool test is positive you will need a colonoscopy.