Since colorectal cancer is a leading cause of death in the Western world, colonoscopy is now being extensively used for early detection of malignant tumors.
In this procedure, the mucous membrane of the colon can be directly visualized through an elongated flexible tube, or endoscope.
Following a thorough washing out of the large bowel, the patient is sedated, and the tube is gently inserted into the anal canal. The interior of the large bowel can be observed from the anus to the cectum.
Photographs of suspicious areas, such as polyps, can be taken and biopsy specimens can be removed for pathologic examination. Although a relatively expensive procedure, it provides a more complete screening examination for colorectal cancer than combined fecal occult blood testing and the examination of the distal colon with sigmoidoscopy.
Colonoscopy can also be used in the diagnosis and treatment of ulcerative colitis and Crohn’s disease.