“Our study answers several of the questions Medicare asked about this procedure,” said Brooks Cash, MD, one of the authors of the study. The study found that the percentage of patients that would have been referred to colonoscopy as a result of CT colonography was 14%, which is similar to what other studies have found in the younger population, said Dr. Cash. “The prevalence of neoplasia (abnormal growths of cells) detected by CT colonography was 9.3% in patients over the age of 65,” which is also similar to the results of other studies involving younger patients,” he said.
Potentially important extracolonic findings were identified in 2.9% of the study group. “The confirmation of low rates of referral to colonoscopy, the prevalence of advanced neoplasia and the prevalence of extracolonic findings makes CT colonography a viable option for Medicare-aged patients,” said Dr. Cash.
The Centers for Medicare and Medicaid Services had also expressed concern about the radiation dose of colonoscopy, said Dr. Cash. “The average effective radiation dose with CT colonography at the National Naval Medical Center in Bethesda, MD (where the study was conducted) was calculated to be 4.24 mSv per CT colonography examination. To put that in perspective, the average yearly radiation exposure of American adults is about 6.2mSv,” Dr. Cash said.
Several previous studies have shown that up to 40% of individuals undergoing CT colonography say they would not have been screened for colon cancer if CT colonography had not been available to them. “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,” said Dr. Cash.
Currently about 50-60% of patients eligible for colon cancer screening undergo any kind of screening examination; “we have calculated in our practice that we could increase screening compliance rates by about 15% if CT colonography was covered by Medicare or third party payers,” Dr. Cash said.
The study appears in the July, 2012 American Journal of Roentgenology, published by the American Roentgen Ray Society.
American Roentgen Ray Society