If an abnormality is discovered during a sigmoidoscopy, a physician will probably suggest a follow-up colonoscopy at a later date. For example, polyps that appear during a sigmoidoscopy indicate the potential for additional polyps in the two-thirds of the colon that can only be viewed during a colonoscopy.

The colonoscopy is similar to a sigmoidoscopy, but the instrument used (a colonoscope) is longer than a sigmoidoscope. Colonoscopy also tends to be more invasive and requires sedation because of greater potential for discomfort.

Treatment will depend on the underlying condition that is causing the abnormality.