Other tests can screen for colorectal cancer. Fecal occult blood testing checks samples of stool for hidden blood that may come from cancers or large polyps, but not all can be detected with this test. Flexible sigmoidoscopy -- a shorter version of a colonoscopy -- sees only the lower third of the colon. And a barium enema uses X-rays to outline the colon and detect polyps.
Bowel preparation is required for sigmoidoscopy and barium enema, however, and the finding of polyps on either test will lead to colonoscopy in order to examine the entire colon and remove all polyps.
A new test, "virtual colonoscopy," allows doctors to examine your colon without going inside with a colonoscope. After a bowel cleansing similar to that used for standard colonoscopy, a computed tomography, or CT, scan of the abdomen and pelvis is performed. To aid in this scan, the colon is inflated with air through a small tube placed in the rectum. The CT images are then examined to detect any polyps and tumors.
Although it is a promising new tool, virtual colonoscopy is not currently recommended for general use, and it is not covered by Medicare and many insurance plans. If polyps are found on this test, it is followed by standard colonoscopy to remove them. Another new test under development checks a stool sample for genetic material (DNA) from cells that are shed from tumors or polyps.
Bottom line: Everyone age 50 or older should undergo a screening test for colorectal cancer or polyps every three to 10 years, depending on one's personal and family medical history. We recommend colonoscopy as the best test for most people, but having any screening test is better than doing nothing. Almost everyone can safely have colonoscopy, but consultation with your physician will help determine which test is best for your situation.
Medical Edge from Mayo Clinic is an educational resource and doesn't replace regular medical care. For health information, visit www.mayoclinic.com.
© 2006 Dear Pharmacist, Inc. Distributed by Tribune Media Services.
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