Before the Centers for Medicare & Medicaid Services (CMS) denied coverage for screening computed tomography (CT) colonography, or “virtual colonoscopy,” in March 2009, the technique was being used appropriately and may have expanded colorectal cancer screening beyond the population tested with standard (“optical”) colonoscopy, according to a new study.

Investigators from the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, conducted a cross-sectional study of all 10,538 asymptomatic Medicare beneficiaries who underwent CT colonography between January 2007 and December 2008. They also looked at a cohort of 160,113 asymptomatic beneficiaries who underwent standard colonoscopy, matched by county of residence and year of examination.

Hanna M. Zafar, MD, MHS, an assistant professor of radiology at the University of Pennsylvania, and colleagues noted in their report for Journal of General Internal Medicine that little was understood regarding whether CT colonography was targeted to the appropriate patient population prior to the CMS decision to halt reimbursement for the test. A University of Pennsylvania School of Medicine statement describing the study results noted that CMS stopped paying for CT colonography in part due to concerns regarding how the procedure was being used in the elderly population.

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Both the American Cancer Society and the American College of Radiology recognize CT colonography as a recommended screening procedure for persons aged 65 years and older, and were among the groups that opposed the CMS decision to stop paying for CT colonography. On average, CT colonography costs $400 to $800, compared with $1,500 to $3,000 for standard colonoscopy, according to the University of Pennsylvania statement.

Zafar’s group learned that during the 2 years preceding the CMS decision to deny payments, CT colonography was targeted to asymptomatic patients with relatively appropriate clinical indications for the procedure who had not received standard colonoscopy. However, CT colonography utilization was lower among minority patients and certain other demographic groups.

The key results of the study were as follows:

  • Overall, 83% of asymptomatic patients referred to CT colonography had at least one clinical indication relatively appropriate for CT colonography.
  • Patients with relatively appropriate clinical indications for screening CT colonography, including presumed incomplete standard colonoscopy, sedation risk, and chronic anticoagulation risk, were more likely to undergo CT colonography than standard colonoscopy. Conversely, patients undergoing high-risk screening, which is an inappropriate indication, were less likely to receive CT colonography.
  • CT colonography utilization was higher among women, patients older than age 65 years, white patients, and those with higher household incomes.

“These findings raise the possibility that future coverage of screening CT colonography might exacerbate disparities in colorectal cancer screening while increasing overall screening rates,” concluded Zafar and associates.