A colonoscopy can identify colon cancer at an early stage, when it’s easiest to treat. But some people hesitate to undergo this invasive procedure, which uses a long, flexible tube with a camera to view the lining of the colon. Now scientists report that a newer technique called virtual colonoscopy can detect most of the large colon polyps that can be found by standard colonoscopy.
Virtual colonoscopy takes a series of x-ray scans of the lower belly. A computer then puts the pictures together to create 3-D images and videos of the inside of the colon.
To compare the accuracy of the new and old techniques, NIH-funded researchers examined more than 2,500 patients, age 50 or older. Each had a virtual colonoscopy followed by a standard one.
Virtual colonoscopy successfully identified about 90% of the patients who had larger polyps, measuring about a ¼ inch or more, that were identified by standard colonoscopy. However, the virtual scan was less effective at detecting smaller polyps.
Both techniques have advantages and drawbacks. Virtual colonoscopy isn’t as accurate as the standard one, but it may be more appealing for those put off by the long tube and sedation used in regular colonoscopy.
A key benefit of standard colonoscopy is that physicians can remove suspicious polyps immediately during the procedure. The long tube—or scope—includes tools for tissue removal. In contrast, patients undergoing a virtual scan must schedule a followup regular colonoscopy to have suspicious polyps removed.
“The most important advice we can give to patients is to get screened,” said study coauthor Dr. Paul Limburg of the Mayo Clinic in Rochester, Minnesota. “How they get screened should be an individual decision based upon discussions between patients and their providers.”