Best Prostate Cancer Radiation?

The most popular form of radiation therapy for prostate cancer may also be the best, a new comparison study finds.

Nearly all men with prostate cancer who opt for external beam radiation get a treatment called intensity-modulated radiation therapy or IMRT. IMRT has almost entirely replaced another type of radiation treatment called 3D conformational therapy - even though it's much more expensive, with little head-to-head evidence showing it works better.

And there's an even newer and even more expensive prostate cancer treatment: proton beam therapy. More and more medical centers are spending hundreds of millions of dollars to build new proton beam therapy centers.

Which treatment really offers a man the best chance of a prostate cancer cure with the fewest side effects? IMRT, according to Ronald C. Chen, MD, MPH, and colleagues at the University of North Carolina at Chapel Hill.

"For prostate cancer in this country, we have completely adopted IMRT," Chen tells WebMD. "I don't see anybody going back to 3D therapy. And thankfully, our study does show it is better in terms of cancer control and reducing long-term side effects. So IMRT is here to stay."

MRT was also shown to be more effective than conventional 3D conformational radiation therapy, the study found. Men treated with IMRT were almost 20 percent less likely to need additional cancer treatment, compared to men treated with conformational therapy.

Reuters reports that in 2000, less than 1 percent of prostate cancers that hadn't spread were treated with IMRT. By 2008, the number shot up to 96 percent.
"For prostate cancer in this country, we have completely adopted IMRT," Chen told WebMD. "I don't see anybody going back to 3D therapy. And thankfully, our study does show it is better in terms of cancer control and reducing long-term side effects. So IMRT is here to stay."

Chen's study is published in the April 18 issue of the Journal of the American Medical Association.

Dr. Tim Carey, director of the Sheps Center at UNC, said in a release, "This type of research is critical, comparing one type of treatment with alternatives, so that patients and their providers can arrive at the best decisions for each individual."

Chen's team didn't conduct a clinical trial. Instead, they compared results for similar Medicare patients who underwent IMRT, 3D conformational therapy, or proton beam therapy for prostate cancer. The data came from Medicare-linked records from the huge U.S. Surveillance Epidemiology and End Results (SEER) database.

The study analyzed data from 6,666 men treated with IMRT, 6,310 men treated with 3D conformational therapy, and 684 men treated with proton beam therapy.

The results:

- Men treated with IMRT were 19% less likely to need additional cancer treatment compared to men treated with 3D conformational therapy."The use of IMRT has skyrocketed in the past 10 years and it's good to see that this study affirms the use of IMRT to reduce side effects and to reduce the risk of additional therapy," Louis Potters, MD, chair of radiation medicine at North Shore University Hospital, Manhasset, N.Y., tells WebMD.