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Common Health Tests (cont.)

Tests for Cancer of the Colon and Rectum

Colorectal cancer is the third most common cancer found in men and women and a leading cause of cancer-related deaths. Screening tests for colorectal cancer include using simple tests to detect the presence of blood in the stool (feces). These tests are called fecal occult blood tests. Doctors may also use an instrument -- the flexible sigmoidoscope -- to examine the lower parts of the bowel directly (where cancers are most commonly found).

  • It is suggested that tests to look for blood in the stool should be conducted annually in everyone over 50 years of age. If there is a strong family history of colorectal cancer, then not only should testing be started much earlier, in the 30s or 40s, but testing may need to be more invasive. The doctor can take a small sample of stool and test it in the office. Sometimes it may be easier for you to provide a stool sample at home using a test kit and mailing the samples to your doctor for testing.
  • For more invasive screening, a colonoscopy is performed. This test uses a long narrow flexible tube to view the entire colon. Talk with your doctor about the use of this test because the doctor will take all factors into account (for example, your family history and past medical history) to determine when you need it.
  • Your doctor may require you to use a strong laxative (called a bowel cleanser) to clear your bowel of fecal contents before colonoscopy. Several medications are available for bowel cleansing, including polyethylene glycol 3350 (GoLYTELY, NuLYTELY), magnesium citrate (Citroma), and senna (X-Prep). These medications produce diarrhea, which can be uncomfortable, but unless the bowel is empty of stool, the test can be limited and may need to be repeated at a later date. Your doctor may also require a special diet, such as a clear liquid diet, starting one to two days before your scheduled colonoscopy.
Medically Reviewed by a Doctor on 6/24/2016
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