Sigmoidoscopy

Sigmoidoscopy is a medical procedure which allows the visualization of the interior of part of the colon and rectum. A scope is used to examine the rectum and last part of the colon, the sigmoid colon, so called because of its curved (S-shaped) configuration. It is sometimes recommended as part of regular colon cancer screening in individuals over 50 years of age.

This procedure does not allow visualization of the entire large intestine. Another related procedure, called colonoscopy, uses a similar, but longer, scope to visualize the entire large intestine and rectum. Therefore, it is a more complete procedure. Just examining the sigmoid colon and rectum could miss abnormalities elsewhere in the large intestine.

Like colonoscopy, this procedure allows the direct visualization of the interior of the intestine and the biopsy or removal of small growths such as early colon cancer or colon polyps.

Because the earliest studies of colon cancer screening were done with sigmoidoscopy, there is some support that regular screening exams after age 50 does decrease the likelihood of dying of colon cancer. However, because colonoscopy allows visualization of the entire colon it is likely that it can achieve an even better outcome in colon cancer screening, prevention and treatment. Therefore, many gastroenterologists (physicians who specialize in diseases of the digestive system) prefer colonoscopy unless there is some contraindication.

Examining the rectum and sigmoid does have the advantages that it is faster and easier to perform. The procedure is very similar in most respects to colonoscopy.