What are the screening tests for colorectal cancer?

A: Several tests can be used to screen for Colorectal Cancer. These tests are used alone or in combination with each other

• Fecal Occult Blood Test (FOBT) - A test that checks for occult (hidden) blood in the stool. At home, using a small stick from a test kit, you place a small amount of your stool, from three bowel movements in a row, on test cards. You return the cards to your doctor's office or a lab, where they're checked for blood. This test is recommended yearly. (If blood is found, you likely will need a follow-up colonoscopy.)

• Flexible Sigmoidoscopy - Before this test, you use a strong laxative and/or enema to cleanse the colon. Flexible sigmoidoscopy is conducted at the doctor's office, a clinic or a hospital. The doctor (or other specially trained health professional) uses a narrow, flexible, lighted tube to look at the inside of the rectum and the lower portion of the colon. During the exam, the doctor may remove some polyps (abnormal growths) and collect samples of tissue or cells for closer examination. This test is recommended every 5 years. (If polyps are found, you will need a follow-up colonoscopy.)

• Combination of Fecal Occult Blood Test (FOBT) and Flexible Sigmoidoscopy - Some doctors recommend having both tests to increase the chance of finding polyps (abnormal growths) and cancers. When used in combination with each other, FOBT is recommended yearly and flexible sigmoidoscopy is recommended every 5 years.

• Colonoscopy - Before this test, you will take a strong laxative to cleanse the colon. Colonoscopy is conducted in a doctor's office, clinic, or hospital. You are given a sedative to make you more comfortable, while the doctor uses a narrow, flexible, lighted tube to look at the inside of the rectum and the entire colon. (This test is similar to flexible sigmoidoscopy, except the tube used is longer and allows the doctor to see the entire colon.) During the exam, the doctor may remove some polyps (abnormal growths) and collect samples of tissue or cells for closer examination. This test is recommended every 10 years. (Colonoscopy is also used as a follow-up test if anything unusual is found during one of the other screening tests.)

• Double Contrast Barium Enema - This test is conducted in a radiology center or hospital. Before the test, you use a strong laxative and/or enema to cleanse the colon. This procedure involves taking X-rays of the rectum and colon after you are given an enema with a barium solution, followed by an injection of air. The barium coats the lining of the intestines so that polyps and other abnormalities are visible on the X-ray. (If polyps are found, you will need a follow-up colonoscopy.)