Sigmoidoscopy Versus Colonoscopy

Last Modified: March 16, 2011


Dear OncoLink "Ask The Experts,"

Is a sigmoidoscopy the same as colonoscopy? If not, which is better?


David Metz, MD, Professor of Gastroenterology at Penn Medicine, responds:

A colonoscopy examines the entire colon from the rectum to the cecum including the rectum, sigmoid colon, descending colon transverse colon, ascending colon and cecum. A sigmoidoscopy is a partial colonoscopy that only examines the left side from the rectum to the sigmoid colon. Colonoscopy usually requires sedation and an oral lavage or preparation is needed but it allows a complete evaluation. Sigmoidoscopy can be done without sedation, only requires enemas for preparation but is limited in its extent. I personally favor a full colonoscopy for screening.

This question and answer was part of the OncoLink Brown Bag Chat Series. See the full transcript of Advances in Colorectal Cancer Screening.