A new study suggests a Medicare reimbursement cut to prostate cancer therapy reduced unnecessary treatments while leaving the rate of prescriptions to patients who could benefit from the drugs the same.

The findings, appearing Wednesday in the New England Journal of Medicine, could help fuel the debate on the effect of financial reforms on patient care.

"We found that physicians respond to reimbursement, but they respond in a way that appears to be beneficial to the patient," Dr. Vahakn B. Shahinian, lead author of the study and an assistant professor of internal medicine with the University of Michigan Medical School, said in prepared remarks.

In the study, the researchers looked at a hormone-blocking therapy used to treat prostate cancer. Clinical results suggest regular injections of the therapy, called androgen deprivation therapy, can help patients with advanced localized prostate cancer or signs of systemic disease.

But for older patients and those with low-risk tumors, its survival benefits might be slight. Plus, the therapy's side effects often outweigh its benefits. Some evidence links the treatment with worsening cardiovascular disease, diabetes and brittle bones.

Nonetheless, throughout the 1990s, ADT was popular among urologists, the authors said, even for patients who might not have benefited. During the decade, use of primary ADT increased by a factor of eight among men over 80 and among older men with low-risk, localized tumors, "patients who would almost certainly be asymptomatic and die from causes unrelated to prostate cancer," the authors wrote.

At the same time, the drugs were profitable. Medicare reimbursed purchases based on 95 percent of the average wholesale price, according to the study. However, a Government Accountability Office report found that doctors generally acquired the drugs at 82 percent of the average wholesale price. For urologists in private practice, the drug could account for 40 percent of revenues, the study said.

But as the new millennium rolled around, the Medicare Modernization Act of 2003 said goodbye to all that. Spurred by historic settlements with drug makers accused of violating federal laws, in 2004, reimbursements were slightly reduced. In 2005, they were then set at 106 percent of the average sale price, as opposed to the average wholesale price, on the basis of actual transactions. This resulted in, effectively, a 50 percent reduction in reimbursement for the products, the study said.

Between 2003 and 2005, price per dose for the treatment fell from $356 to $176.

While it was known this resulted in a slight decrease in the therapy's use, the researchers of the current study wanted to see whether usage fell across the board, affecting even patients who could benefit from it, or was restricted to patients who likely didn't need the treatments.

For the study, the researchers looked at records of around 55,000 men who had gotten a prostate cancer diagnosis between 2003 and 2005. They found inappropriate use of ADT dropped substantially after reimbursement cuts took effect, reaching levels seen in the mid-90s, as they went from around 39 percent in 2003 to 26 percent in 2005. At the same time, there was little change in usage for appropriate use, the study authors said, increasing from 79 percent in 2003 to 82 percent in 2005.

Discretionary use of the drug, for cases where there was uncertain benefit, also fell, but only moderately, the authors said.

This isn't the first time the suggestion has been made that reimbursements drove use. Last year, a brace of editorials in prominent medical journals highlighting the risks of ADT wondered if it was overprescribed because of reimbursements.

Of course, doctors have only recently begun to understand the drug's side effects. Still, Dr. Shahinian said that increasing knowledge of the therapy's risks is unlikely to have played the decisive role here. He points out that papers showing cardiovascular and diabetes risks didn't start appearing until 2006, after the period included in his study. And the first major study demonstrating a serious side effect, a paper in the New England Journal of Medicine showing the link with fractures, and put out by Dr. Shahinian's team, didn't appear until 2005.

"The reimbursement dropped drastically over 2003 to 2005, but it already dropped 15 percent in 2004," he told DOTmed News. "In 2004, there wouldn't have been a major recognition of side effects, and we already saw a drop, predominantly in potentially inappropriate use."

But Shahinian acknowledges that reimbursement is not the only culprit here. Psychological, and not mercenary factors were likely at work, especially for patients in a category where ADT would likely not help but where there really aren't many options other than waiting.

"It's hard to sell to a patient, 'Let's just watch, let's just do nothing,'" he said.

"I think pressure to do something in the face of a cancer diagnosis absolutely plays a role," he said. "But we're saying the profit motive may help push or sway the factors in favor of using it. The fact when you take away the profit motive that use drops, provides some credibility to that hypothesis."