This procedure also allows other instruments to be passed through the colonoscope. In this way, colonoscopy may help to avoid surgery or to better define what type of surgery may need to be done. A shorter version of the colonoscope is called a sigmoidoscope, an instrument used to screen the lower part of the large bowel only. The colonoscope, however, is long enough to inspect all of the large bowel and even part of the small intestine. Colonoscopy is a safe and effective way to evaluate problems such as blood loss, pain, and changes in bowel habits such as chronic diarrhea or abnormalities that may have first been detected by other tests.
Colonoscopy can also identify and treat active bleeding from the bowel.
Colonoscopy is also an important way to check for colon cancer and to treat colon polyps - abnormal growths on the inside lining of the intestine. Polyps vary in size and shape and, while most are not cancerous, some may turn into cancer. However, it is not possible to tell just by looking at a polyp if it is malignant or potentially malignant. This is why colonoscopy is often used to remove polyps, a technique called a polypectomy. There are important steps that you must take to prepare for the procedure.