Probe Can Tell Whether Colon Polyp Is Benign Without Removal
May 28, 2008
A probe so accurate that it can tell whether or not a colon polyp is benign or pre-cancerous--without removing it for examination by a pathologist--may transform the way colonoscopies are done, say researchers from the Mayo Clinic in Jacksonville, FL.
The probe uses a technology known as a high resolution confocal endomicroscopy. It is manufactured by Mauna Kea Technologies and is already on the market, so theoretically anyone can use it.
"But there is a learning curve involved," Mayo Clinic doctor Michael Wallace, M.D., MPH and professor of medicine, tells DOTmed News. "We bought one last October and completed 100 procedures. The first 50 were not as accurate in identifying polyps as the second 50, in which doctors were 98 percent accurate in identifying whether polyps were either precancerous or benign. We'd like to become 99.9 percent accurate, before we can say we mastered the procedure."
For the next year or two, Dr. Wallace's team will use the scope experimentally. Currently, he is conducting a study of 50 patients with 100 polyps. Then he wants to confirm the results at other hospitals to make sure the procedure can be done by any gastroenterologist. Once doctors become adept at the procedure, the scope will "allow us to look at the tissue in its native state without removal and hopefully determine if it's diseased or abnormal," Dr. Wallace says.
Now, he says, "Half of all polyps surgically removed during colonoscopy procedures are benign so this virtual biopsy will save the expense of a pathologist, make the time it takes to do a colonoscopy shorter, and reduce complications that still occur about 1 percent of the time when tissue is removed."
The device is a small imaging tool, which can be attached to a variety of endoscopes. When a suspicious polyp is seen during a colonoscopy, a physician uses a small amount of fluorescent contrast to illuminate the area and the probe magnifies it 1,000 times.
Dr. Wallace says another very sensitive probe is being marketed by Pentax Endoscopy, but that one is an endoscope with a built-in confocal system. The main difference between the two scopes, he says, is that the one he is using--which is only 1/16th of an inch in diameter--can be used with any medical endoscope already being used for colonoscopy.
Dr. Wallace's study, supported by the American Society for Gastrointestinal Endoscopy, was presented at Digestive Disease Week, a scientific meeting of gastrointestinal specialists and researchers held last week in San Diego.