A new study of 1,400 Medicare-age patients provides fodder for advocates of virtual colonoscopy as an alternative to invasive colonoscopy.
The Centers for Medicare & Medicaid Services in 2009 ended payment for virtual colonoscopy, citing inadequate research on the over-65 population. Concerns also have been raised about radiation dose.
The study, published in the American Journal of Roentgenology, found abnormal cells in 9.3 percent of patients who were older than 65, a rate similar to the general population. Fourteen percent of the 1,400 patients scanned would have been referred for invasive colonoscopy. The radiation dose averaged 4.24 mSv, less than the 6.2mSv average yearly radiation exposure of American adults.
In addition, 40 percent of those screened said they would not have had the procedure done as invasive colonoscopy.
"Our study answers several of the questions Medicare asked about this procedure," study co-author Brooks Cash, M.D., said in an announcement touting the study.
According to the Centers for Disease Control and Prevention's most recent statistics, about half of Americans who should be screened for colon cancer do not undergo a colonoscopy.
"This is the real value of CT colonography--offering an alternative, high-quality, total colonic preventative screening to a large percentage of the population that either refuses or is unable to undergo colonoscopy," Cash said of the study, conducted at the National Naval Medical Center in Bethesda, Md., and the University of Wisconsin.
Previous research has found virtual colonoscopies to be as effective as traditional colonoscopies at detecting large and medium-sized polyps that can be precursors to colon cancer. They don't require anesthesia and are much less expensive than the standard procedure, since there's no need for an anesthesiologist or pathologist to be present. The downside: Questionable polyps cannot be removed on the spot, as in the invasive procedure.
David Bernstein, chief of the division of hepatology at North Shore University Hospital in Manhasset, N.Y., told HealthDay News he did not back a change in Medicare policy. He said that a major shortcoming of the study was that the patients did not undergo the invasive procedure as well, so there's no way to determine whether all the questionable polyps were found.
Brett Bernstein, director of endoscopy in the division of digestive diseases at Beth Israel Ambulatory Endoscopy Services in New York, concurred that the virtual procedure does not supersede invasive colonoscopy.
In 2010, doctors at the Mayo Clinic in Scottsdale, Ariz., found that CT scans of the colon, when used in combination with a technique called adaptive statistical iterative reconstruction, could produce high-quality images with about half the normal radiation dose, at approximately 2.5 mSv.