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Tuesday, December 02, 2003A new study finds that virtual colonoscopy, a method that uses a C.T. scanner for colon cancer screening, can be just as effective as traditional colonoscopy in finding polyps, the mushroomlike growths from which most cancers arise. Patients having the 15-minute virtual screening test simply lie down and hold their breath for about 10 seconds, exhale, then hold their breath again while a C.T. scanner X-rays their colons, creating detailed, three-dimensional images of the walls. With traditional colonoscopy, patients are sedated while a doctor threads a long flexible tube into the colon, spending half an hour viewing its walls in much the same sort of detail. Then they wait in a recovery room for about an hour as the sedative wears off. But, it's as expensive as a traditional colonoscopy (anywhere from $500 to $2,000) and this is the first study that found it to be effective: Virtual colonoscopy has been around for nearly a decade, but it has never been on the recommended list of screening tests. In previous studies it missed as many as half of even the large polyps that are most worrisome. The difference this time, said Dr. Pickhardt, is in the method. The study researchers used a computer program that revealed the colon in three dimensions. Most other virtual colonoscopy has involved two-dimensional slices created from C.T. scan images. The patients in the new study also drank a fluid that labeled fecal material so doctors did not confuse it with polyps. The accompanying editorial in the New England Journal (available without subscription today, although you have to download a pdf version) points out that the other difference between this study and others is that the researchers didn't include the non-precancerous polyps the virtual colonoscopy failed to find. That may not make much of a difference clinically since those types of polyps don't go on to become cancer, but the other interesting aside is that only 50% of the study subjects said they would choose the virtual colonoscope over the conventional one if given a choice. That's not too surprising. Most of my patients tell me the worst part of the colonscopy is preparing for it (cleaning the bowels out completely.) And if a virtual colonoscope finds polyps, then the patient has to go on to a regular colonoscope to have them removed, which means another prep. Yuk. posted by Sydney on 12/02/2003 08:19:00 AM 0 comments 0 Comments: |
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