What is a Colonoscopy?

Carolyn Vachani, MSN, RN, AOCN
Last Modified: June 16, 2002


Dear OncoLink "Ask The Experts,"
What is a Colonoscopy?  


Carolyn Vachani, MSN, RN, AOCN, OncoLink's Clinical Trials Coordinator, responds:

A colonoscopy is a procedure that utilizes a colonoscope to examine the rectum and entire colon. The colonoscope is a long, slender, flexible tube that has a light and a camera, which allow the bowel wall to be seen by the physician on a television screen. In addition, the colonoscope contains instruments that allow the doctor to take samples of tissue from the bowel wall when necessary. The colonoscope is able to view the whole colon, unlike the sigmoidoscope, which can only view about ½ the colon. The procedure does require the patient to undergo a bowel preparation the day before the procedure, which needs to be more complete than the preparation for sigmoidoscope. This preparation may include laxatives, enemas, and a clear liquid diet. The American Cancer Society recommends that people without a family history of colon cancer have this test every 10 years for screening, or a sigmoidoscope every 5 years.