Proton-beam therapy, an expensive and emerging treatment for prostate cancer, is no more effective than standard radiotherapy in patients one year after they underwent treatment, according to a new study's findings.

The study (PDF), slated to be published Friday afternoon in the Journal for the National Cancer Institute, compared toxicity in 24,647 Medicare beneficiaries who received either proton radiotherapy or intensity-modulated radiotherapy in 2008 or 2009.

It was conducted by researchers at the Yale University School of Medicine in New Haven, Conn.

Although the costs of treatment are higher than those for standard radiotherapy—the study found that median Medicare reimbursement for proton-beam therapy was nearly $14,000 higher—proponents of proton radiotherapy say that new treatment decreases side effects that include gastrointestinal and genitourinary toxicity.

Proton-beam therapy is a relatively new cancer treatment that is growing in use in the U.S. There are 10 proton-beam therapy centers in the U.S.; seven of these are owned by hospitals.

ProCure Treatment Centers, a New York-based for-profit operator of proton-beam therapy centers, operates three facilities.

The study found modest associated reduction in genitourinary toxicity in patients who had received proton radiotherapy six months earlier. However, there was no difference one year after treatment.

There was no statistically significant difference for gastrointestinal toxicity in patients at either six months or 12 months after treatment.

"The relative reimbursement of new medical technologies needs to be considered carefully so that physicians and hospitals do not have financial incentive to adopt a technology before supporting evidence is available," the researchers wrote in the study.

The study also found that younger patients were more likely to receive proton radiotherapy, as were patients who were white, who lived in more affluent areas and in states that did not require a certificate of need, and had less comorbidity.