ANNOUNCER: Cancer of the colon and rectum is called colorectal cancer, and it's the fourth most common cancer in the United States.
Doctors recommend that everyone over age 50 should be regularly screened for colorectal cancer, but some people should be screened earlier.
RICHARD GOLDBERG, MD: If you have a family history of colon cancer you should be screened 10 years before the youngest affected relative. So if a relative of yours - a sister or a parent - had colon cancer at the age of 40, you ought to be screened at 30.
ANNOUNCER: There are several tests that are used to screen for cancers of the colon.
EDWARD CHU, MD: The traditional test that the American Cancer Society and the Centers for Disease Control have strongly recommended is fecal occult blood testing. So to simplify that, that is actually testing one's stools for the presence of blood, as well digital rectal exam.
ANNOUNCER: A sigmoidoscopy is a test performed by a gastroenterologist. A tube with a tiny TV camera and light is inserted into the rectum and distal portion of the colon, to screen for abnormalities.
RICHARD GOLDBERG, MD: The trouble is the sigmoidoscopy only looks at the bottom foot and a half of the colon and the colon is about 6 feet long.
ANNOUNCER: In order to examine the entire colon, gastroenterologists prefer to perform colonoscopies.
EDWARD CHU, MD: So what colonoscopy is, is a - basically a tube that's inserted through the rectum and goes all the way up through the large intestine. So it can visualize the entire colon.
ANNOUNCER: Sometimes abnormal growths called polyps are found in the colon during these exams.
RICHARD GOLDBERG, MD: Many times, early stage colorectal cancers will develop on a polyp. And sometimes these polyps are actually on a stock so that they sort of look like a mushroom with the top of the polyp being the polyp and then the stem of the mushroom being the stock.
What a colonoscopist can do is actually put a snare around the bottom of the mushroom and use a little electric current to pull that off and retrieve it.