What Is a Flexible Sigmoidoscopy?

A flexible sigmoidoscopy is a key piece of equipment used in screening for colon cancer. A flexible tube 60cm (approximately 23 inches) in length, the sigmoidoscope device contains a camera for video inspection of the colon area.

Usage

• Flexible sigmoidoscopy is one of two methods used to detect colon cancer via rectal bleeding source identification, structural abnormality, and evidence and sampling of polyps, the malignancy of which are a precursor to cancer.

Sigmoidoscopy Versus Colonoscopy

• The two procedures are relatively similar in that they perform a video probe of the colon area and can sample or remove polyps (small irregular growths on the colon wall). The major difference between the two is the area which may be inspected. For example, a colonoscopy is able to view the entire length of the colon, while the sigmoidoscopy may only access the lower portion.

  The effectiveness and accuracy of both procedures are increased in tandem with a fecal occult blood test (FOBT). This test can be used to indicate cancer in any area of the colon, and is based upon the ability to detect trace amounts of blood in the stool, indicating potential for a number of colon issues.

Procedure Preparation

• The colon must be cleansed in order to obtain the most accurate results. This generally involves pre-procedure dietary modifications and the use of a prescription laxative as determined by the physician, based on the symptoms. This part of the procedure may not be used oif there is evidence of excessive diarrhea.

  Generally, no change in the use of prescription medication will be required. The exception to this would be any medication or over the counter product (such as aspirin) which acts as a blood thinner, reducing the effectiveness of the FOBT as well as increasing the risk of bleeding in the event of a polyp biopsy.

Procedure

• Prior to the start of a flexible sigmoidoscopy procedure, a general anesthesia is usually administered. The procedure rarely causes measurable pain, the most common symptoms being a sensation of pressure, cramping, bloating, or a feeling of fullness. The patient will lie on their left side, and the sigmoidoscope is inserted through the anus and slowly moved through the rectum and into the lower colon. The colon is inspected using a television monitor, allowing examination of the colon walls. Biopsies (tissue sample) of any suspect area may be taken during this time. The procedure usually takes no more than 15 minutes and can be completed in as little as five minutes.

Risks

• Since it is administered by a trained professional in a controlled setting, the risks associated with the procedure are minimal. Most common, though rare, are puncture of the colon wall (requiring surgery to repair) and bleeding at the site of the biopsy.