Suspicion of colorectal cancer usually arises at the doctor’s office on the basis of the patient’s symptoms. There are many different methods available for diagnosing colorectal cancer. What research methods are used and the extent to which they are implemented will affect the clarity of the diagnosis.
Manual examination of the rectum
In case of suspected cancer of the colon or rectum, rectal is usually examined first manually. The doctor does this by palpating with his finger through the anus, looking for unusual nodules and paying attention to the presence of blood in the stool.
Colonoscopy is a safe, clean and realiable scopic procedure, which takes about an hour. Colonoscopy uses a long, flexible and slender tube attached to a video camera and monitor to view your entire colon and rectum. If any suspicious areas are found, your doctor can pass surgical tools through the tube to take tissue samples (biopsies) for analysis. About half of all colorectal cancers are found with colonoscopy.
Instead of or in addition to colonoscopy, a radiologic examination may be performed. During the examination, the X-ray doctor inserts a tube into the rectum through which contrast medium and air are injected. The device produces images of the intestine filled with contrast medium. The method is nowadays little used because it does not provide biopsies and is not as reliable as a colonoscopy study.