A decision by the Centers for Medicare and Medicaid Services to deny reimbursement for CT colonography screening has shocked radiologists. News that CMS had deemed evidence inadequate to grant coverage left imagers not only dismayed but in disbelief.

"Given the cumulative evidence that strongly supports the use of CTC for screening, this decision defies logic," said Dr. Perry J. Pickhardt, an associate professor of radiology at the University of Wisconsin Medical School in Madison.

In a Proposed Decision Memorandum issued Feb. 11, CMS suggested that the existing scientific evidence is inadequate to conclude that CTC improves net health benefits for Medicare beneficiaries. CMS thus decided that CTC for colorectal cancer screening should remain uncovered.

A final decision from CMS will be issued after a 30-day mandatory comment period.

Although CTC is a promising technology, questions on its use need to be answered with well-designed clinical studies that focus on the Medicare population, CMS said in the proposed decision memo. Physicians and beneficiaries should choose among several other colorectal cancer screening tests currently covered under Medicare until sufficient evidence to support CTC becomes available, it said.

The decision is especially shocking in view of the fact that colorectal cancer is readily preventable yet only a minority of Medicare beneficiaries are screened by existing covered methods, Pickhardt said.

Some of these methods, such as the fecal occult blood test, are not even preventive, he said.

"CTC is not only a suitable screening test, but likely the single best test when clinical efficacy, cost-effectiveness, and safety are all considered," he said.

Pickhardt was first author for a landmark 2003 study of CT colonography (NEJM 2003:349(23):2191-2003). The Department of Defense study of more than 1200 patients showed that CTC equaled the diagnostic power of optical colonoscopy for identifying suspicious colon polyps of greater than 6 mm.

The American College of Radiology also called the CMS ruling disappointing. The college thought there was enough evidence for CMS to include CTC in its regimen of colorectal screening studies based on results of the ACR Imaging Network trial published last fall, according to Dr. Bibb Allen, chair of the ACR's commission on economics.

"We made a fairly clear case," Allen said.

As it studies decision details, the ACR plans to address CMS concerns about the lack of studies applicable to the Medicare population, he said.

In its statement, CMS said it would be willing to review the decision. It cautioned, however, that even if it finds that CTC is clinically effective, additional information and public comments would be needed to determine the test cost-effectiveness.

It was not clear what rationale had been used to determine colonoscopy's cost-effectiveness when it was matched against CTC's at the Medicare evidence development and coverage advisory committee (MedCAC) in November last year, according to Allen. Those criteria would have to be reviewed as well because it was not clear that hospital costs, such as anesthesia, had been factored in.

Data show that CTC is competitive with optical colonoscopy regarding cost-effectiveness, Allen said.

"One thing that the college would do is make sure that we are comparing apples to apples," he said.

CMS is requesting public feedback on the proposed determination and announced it will issue a final decision after considering comments.