'Virtual' Colonoscopy Safe, Effective for Medicare Patients: Study
But experts say colonoscopy still trumps CT-guided scan for now
MONDAY, July 2, 2012 (HealthDay News) -- A new study of seniors provides support for using "virtual" colonoscopy -- which is not currently covered by Medicare -- as a screening tool for colon cancer.
Virtual colonoscopy, formally called CT colonography, uses CT scanning to take a noninvasive look at the colon, unlike invasive colonoscopy. The federal government has sought more data about the use of CT colonography before deciding on whether or not to cover its cost.
"Our study answers several of the questions Medicare asked about this procedure," study co-author Dr. Brooks Cash said in a news release from the American Roentgen Ray Society.
The study authors looked at more than 1,400 patients who received CT colonography and found that 14 percent of them would have been referred to get a colonoscopy. Virtual colonoscopy detected abnormal cells in 9.3 percent of patients who were older than 65, the researchers found. Cash said that rate is similar to those in younger patients.
The results suggest that virtual colonoscopy is "a viable option for Medicare-aged patients," said Cash.
According to Cash, the U.S. Centers for Medicare and Medicaid Services (CMS) was concerned about the amount of radiation that patients might be exposed to during virtual colonoscopy. The average effective radiation dose turned out to be less than the average annual radiation exposure of American adults, he said.
Research has suggested that 40 percent of people who underwent virtual colonoscopy wouldn't have otherwise gotten screened for colon cancer if they hadn't been able to undergo the procedure.
"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.
CT colonography still requires that patients undergo the unpleasant process of cleansing their bowels before the procedure, just like regular colonoscopies. However, patients aren't sedated during the colonography and may feel less discomfort.
Like regular colonoscopies, the purpose of the procedure is to detect signs of colon cancer.
Two experts said that while the results of the study are impressive, invasive colonoscopy remains the method of choice in spotting lesions in the colon.
"CT colonoscopy detected lesions in 14.5 percent of the patient's screened. While this is impressive, the current standard for the detection of adenomas with standard optical colonoscopy is 20 to 25 percent," Dr. David Bernstein, chief of the division of hepatology at North Shore University Hospital in Manhasset, N.Y. "A major shortcoming of this study is that it is retrospective and not all patients undergoing CT colonoscopy were referred for optical colonoscopy. Therefore, there is no way of determining the potential miss rate of colonic polyps or colon cancer in the patients only receiving CT colonography."
"Because of this, I do not feel that [Medicare's] policy should be changed based upon this single study," Bernstein said.
Another expert said CT colongraphy should be offered, but it does not supersede colonoscopy.
"In general, the ability to offer patients a menu of choices for colon cancer screening is desirable, as it can capture as many patients as possible, and thus improve early detection and prevention rates," said Dr. Brett Bernstein, director of endoscopy in the division of digestive diseases at Beth Israel Ambulatory Endoscopy Services, in New York City.
"Colonoscopy is still the gold standard as it is both an early detection and preventative exam," he added. "CT colonography should definitely be considered as a viable choice for screening, although it is only an early detection exam and any findings would need to be followed by a colonoscopy."
The study appears in the July issue of the American Journal of Roentgenology.
For more on CT colonography, head to the U.S. National Library of Medicine.