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Colon Cancer (cont.)

Exams and Tests

If you are having rectal bleeding or changes in your bowel movements, you will undergo tests to determine the cause of the symptoms.

  • Your health care provider may insert a gloved finger into your rectum through your anus.
  • This test, called a digital rectal exam, is a quick screen to make sure that any bleeding is actually coming from your rectum.
  • This is not painful, but it is mildly uncomfortable for some people. It takes only a few seconds.

You may have a test called a colonoscopy.

  • This is a test that allows a specialist in digestive diseases (a gastroenterologist) to look at the inside of your colon.
  • This test looks for polyps, tumors, or other abnormalities.
  • Colonoscopy is an endoscopic test. This means that a thin, flexible plastic tube with a tiny camera on the end will be inserted into your colon via your anus. As the tube is advanced further into your colon, the camera sends images of the inside of your colon to a video monitor.
  • Colonoscopy is usually done with sedation and is not an uncomfortable test for most people. You will first be given a laxative solution to drink that will clear most of the fecal matter from your bowel. You will be allowed nothing to eat for a short period before the test and a liquid diet only for a day before the test.
  • Flexible sigmoidoscopy is similar to colonoscopy but does not go as far into the colon. It uses a shorter endoscope to examine the rectum, sigmoid (lower) colon, and most of the left colon.
  • CT colonography is another way to examine the colon. Again, the stool must be cleared from the colon before the examination. Colonoscopy allows sample to be taken (biopsies) if an abnormality is found. Colonography does not allow that, as there is no direct visualization of the interior of the colon.

Air-contrast barium enema is a type of X-ray that can show tumors.

  • Before the X-ray is taken, a liquid is introduced into your colon and rectum through your anus. The liquid contains barium, which shows up solid on X-rays.
  • This test highlights tumors and certain other abnormalities in the colon and rectum.
  • Other types of contrast enemas are available.
  • Air-contrast barium enema frequently detects malignant tumors, but it is not as effective in detecting small tumors or those far up in your colon.

If a tumor is identified in the colon or rectum by a biopsy performed during a sigmoid or colonoscopy, you will probably undergo CT scan of your abdomen and a chest X-ray to make sure the disease has not spread.

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