A sigmoidoscopy is a medical procedure which involves the use of a tool called a sigmoidoscope to look into the sigmoid colon, the lower part of the colon. This procedure is sometimes recommended for colon cancer screening, and it can also be used as a diagnostic tool to determine why a patient is experiencing diarrhea, rectal bleeding, and other symptoms related to the gastrointestinal tract. It is important to remember that a sigmoidoscopy is not the same thing as a full colonoscopy, which actually looks at the entire colon, and therefore it is possible to miss signs of colon cancer or disease with a sigmoidoscopy.
There are two basic types of sigmoidoscopy. In a flexible sigmoidoscopy, a physician uses a flexible probe which is gently inserted into the rectum and slowly extended into the sigmoid colon. In a rigid sigmoidoscopy, a rigid probe is used; because of the greater discomfort associated with this technique, most patients and physicians prefer flexible sigmoidoscopies. Dur