Colonoscopy useful to spot other problems

Virtual colonoscopy, an increasingly popular technique that uses CT scans instead of invasive endoscopy to identify colon polyps, can identify many medical problems outside the colon, making it a more valuable tool than researchers had previously believed.

In 500 men undergoing virtual colonoscopy, 45 had significant problems outside the colon, including aneurysms and other cancers, researchers from the University of California, San Francisco, report today in the journal Radiology.

"We found that virtual colonoscopy can detect cancers and other conditions that would be missed with conventional colonoscopy with a negligible radiation risk, roughly comparable to that of a routine CT scan of the abdomen," said the principal author, Dr. Judy Yee, a radiologist at the University of California.

Although the American Cancer Society recommends that all Americans, even those without cancer histories in their family, be screened regularly for colon cancer beginning at age 50, less than 30 percent do, partly because of the length and discomfort of conventional colonoscopies.

Virtual colonoscopy - in which doctors scan a patient's colon with 20 seconds of X-rays - is far less invasive than conventional colonoscopy - in which a patient is obliged to down a salty flask of laxatives before being sedated for a procedure in which a long metallic tube is inserted.