In prostate cancer treatment, newer might not necessarily be better.

University of North Carolina at Chapel Hill research has found that intensity modulated radiation therapy, or IMRT, is as effective and produces fewer side effects than the newer and more expensive proton therapy. And IMRT is better than conventional radiation therapy for reducing side effects and preventing cancer recurrence. The comparative effectiveness study results were published in the April 18 issue of the Journal of the American Medical Association.

IMRT, CRT and proton therapy are three types of radiation treatment intended to minimize radiation exposure to surrounding organs with a radiation dose that targets the tumor. But proton therapy is expensive and its effectiveness versus other radiation treatments had not been studied in comparative effectiveness studies, according to UNC. Meanwhile, IMRT has replaced conventional CRT as the main prostate cancer radiation treatment. But Dr. Ronald Chen, assistant professor of radiation oncology and a research fellow at the Sheps Center for Health Services Research at UNC, said that the change was made without much supporting data.

“This study validated our change in practice, showing that IMRT better controls prostate cancer and results in fewer side effects,” Chen said in a statement.

UNC researchers used Surveillance, Epidemiology and End Results (SEER) Medicare data from 2000 through 2009 that included information from about 13,000 patients with non-metastatic prostate cancer. The comparative effectiveness research aimed to provide new research-based evidence on the benefits and harms of different treatments. Outcomes measured were gastrointestinal events such as rectal bleeding or diarrhea and urinary adverse effects, including erectile dysfunction. Researchers found that that men treated with IMRT were less likely to receive a diagnosis of gastrointestinal adverse effects and hip fracture, but more likely to receive a diagnosis of erectile dysfunction. IMRT patients were nearly 20 percent less likely to receive additional cancer therapy.

Proton therapy company ProCure was quick to denounce the UNC research findings. Dr. Eugen Hug, medical director and chief medical officer of the New York-based company, said in a statement that proton therapy has consistently resulted in reports of a low incidence of side effects. Hug said that prospective studies that yielded these results are “higher level” than UNC’s retrospective study. Hug said that the prospective proton therapy studies had low incidence of side effects, a contrast to a high number of gastrointestinal events found in the UNC study.

The UNC study did not take into account factors that could affect the rate of injury; a query of the SEER database is insufficient for such an analysis, Hug said. Hug said that clinical trials being conducted by the Proton Collaborative Group, an association formed to conduct proton therapy studies, would provide that analysis.

The UNC research was conducted through a contract from the U.S. Department of Health and Human Services’ Agency for Healthcare Research and Quality.

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