What is a colonoscopy?

Video: Fact Check: Colonoscopies

A colonoscopy is an examination of the inside of the colon and rectum. This simple procedure helps find ulcers, growths (polyps), and areas of inflammation inside the colon. It can help diagnose problems related to bleeding, abdominal pain or changes in bowel habits. If polyps are found, they can be removed at the same time, eliminating the chances of the polyp becoming cancer later on. A colonoscopy is also used as a screening tool to detect colorectal cancer.

Screening is the best way to find colorectal cancer early, because it looks for signs of cancer in people who do not have any symptoms. In many cases, these tests can find colorectal cancers at an early stage and greatly improve treatment outcomes.

How does it work?

The colonoscope has a small camera attached to a flexible tube that can reach the length of the colon. An anesthesiologist or nurse anesthetist will administer high level intravenous sedation before the procedure. You should feel no pain and not remember the procedure. You will lie on your left side with your knees drawn up toward your chest.

The colonoscope is inserted through the anus. It is gently moved into the beginning of the large bowel and slowly advanced as far as the lowest part of the small intestine. The doctor may take tissue samples with tiny biopsy forceps inserted through the scope. Polyps may be removed with snares, and images may be taken. You will need to completely cleanse your intestines. A problem in your large intestine that needs to be treated may be missed if your intestines are not cleaned out. Your healthcare provider will give you the steps for cleansing your intestines.

You may have abdominal cramping after the procedure, in general this is mild. Our physicians use carbon dioxide to expand the colon instead of air which dramatically reduces cramping after the procedure.

Who should be screened with a colonoscopy?

Colorectal Cancer
Starting at age 50, both men and women should follow one of these screening plans:

  • Flexible sigmoidoscopy every 5 years*, or
  • Colonoscopy every 10 years, or
  • Double-contrast barium enema every 5 years*, or
  • CT colonography (virtual colonoscopy) every 5 years*

* If the test is positive, a colonoscopy should be done.

Talk to a health care provider about which screening is best for you and how to make an appointment.

If you are at high risk of colon cancer based on family history or other factors, you may need to be screened using a different schedule. Ask your health care provider about when you should begin screening and how often.

Colon Cancer: Catching It Early
(The above text link with infographic is provided by the American Cancer Society®.)

Colonoscopy may be done for other reasons such as:

  • Abdominal pain, changes in bowel movements, or weight loss
  • Abnormal changes (such as polyps) found on sigmoidoscopy or X-ray tests (CT scan or barium enema)
  • Anemia due to low iron (usually when no other cause has been found)
  • Blood in the stool, or black, tarry stools
  • Follow-up of a past finding, such as polyps or colon cancer
  • Inflammatory bowel disease (ulcerative colitis and Crohn's disease)