Three tests are available to tell whether polyps are present. It is done with a lighted, flexible, hollow tube, which is about the thickness of a finger. The sigmoidoscope is inserted into the anus, through the rectum and into the large intestine. With the sigmoidoscope, the doctor can see whether polyps or cancer are present. At the time of sigmoidoscopy, a biopsy forceps may be inserted through the inside of the sigmoidoscope to remove a bit of tissue for examination under the microscope.
Most patients feel a little pulling sensation or no discomfort when having flexible sigmoidoscopy.
Before having this exam, the patient must undergo a preparation for flexible sigmoidoscopy. This preparation, which may include a liquid diet, enema and laxatives, clears stool from the colon so that it may be inspected. Colonoscopy - this is an exam of the rectum and the entire colon. It is done with a lighted, flexible, hollow tube slightly larger in diameter than an enema tube. It permits the doctor to see much farther into the bowel than with the sigmoidoscope.