Proton radiotherapy (PRT), an expensive cancer treatment that has received much buzz, did not show any less treatment-related toxicity for prostate cancer patients between 0 and 12 months than less costly intensity-modulated radiotherapy (IMRT), according to a new study published in the Journal of the National Cancer Institute.

The study looked at Medicare beneficiaries age 66 or older who received PRT or IMRT for prostate cancer between 2008 and 2009. Each PRT patient was matched with an IMRT patient with similar clinical and socioeconomic backgrounds. While PRT showed a reduction in genitourinary toxicity in the first six months, when measuring toxicity out to 12 months that difference disappeared.

"IMRT is the standard of care for prostate cancer, and it already has an outstanding side effect profile," study author James Yu told DOTmed News. "And so we were curious as to whether this more resource intensive and more extensive therapy was better than an already excellent treatment."

According to the study, Median Medicare reimbursement was $32,428 for PRT and $18,575 for IMRT.

Proton therapy has received attention because studies have suggested it causes fewer side effects than traditional radiation. Protons deposit a low dose of radiation when they enter the body, releasing most of it at the end of their path. In theory, that allows oncologists to direct radiation treatment more precisely and reduce damage to tissue surrounding a tumor.

The therapy has been found to improve late side effects in some pediatric brain cancers, but few long-term studies have been performed on other cancers.

"I think the problem with treating the prostate is that you have to add a margin of error because you can't position the patient in the same position every treatment," said Yu. "Also, the rectum is immediately adjacent to the prostate, and the urethra travels right through the prostate, so you can't really avoid those even if you have perfect dosimetry."

There are currently 11 proton therapy centers in the United States. The University of Florida Proton Therapy Institute, which recently installed technology that tracks tumors as they move, responded to Yu's study with data it collected after five years of providing treatment. The Institute says proton therapy resulted in minimal bowel and urinary side effects as well as 99 percent survival in low and intermediate cases, and 74 percent survival in high-risk prostate cancer patients.

Still, Yu as well as organizations such as the National Cancer Institute, Institute of Medicine and the Agency for Healthcare Research and Quality have called for more randomized studies to measure the value of the treatment before more facilities call for it in prostate cancer.

"I think proton therapy is an important part of our treatment as radiation oncologists but the emphasis on prostate cancer treatment may be misplaced," said Yu.