An emerging type of radiation therapy for treating localized prostate cancer called proton therapy appears to be no better in reducing the risk of disease recurrence than the current standard of radiotherapy care, intensity-modulated radiation therapy (IMRT), but it is far more costly and also appears to increase the risk of gastrointestinal complications. These findings appear today in JAMA as part of the journal’s comparative effectiveness research theme issue.
Prostate cancer is the most common malignancy in men, resulting in about 200 000 diagnoses and 30 000 deaths each year in the United States. The ability to diagnose prostate cancer early and the slow-growth nature of the disease give men and their physicians various treatment options. About 30% to 40% of men with prostate cancer choose to undergo radiation; others may opt for watchful waiting or surgery, depending on such factors as age, the stage and grade of their cancer, and their personal preferences.
The JAMA researchers, using data from the SEER-Medicare database (a linkage of 2 large population-based sources of data that provide detailed information about Medicare beneficiaries with cancer), also found IMRT did better than a less recently developed form of radiotherapy, conformal radiation, but this efficacy was not determined until after IMRT use grew from 0.15% of patients undergoing radiation in 2000 to 95.9% in 2008.
Ronald C. Chen, MD, MPH, of the University of North Carolina at Chapel Hill and a study coauthor, discusses his team’s findings:
“There are all these treatment options out there for men with prostate cancer. There’s watchful waiting, surgery, or radiation. Very few studies have compared therapies head to head, and comparative effectiveness research, which we did, is designed to do that.
“In the past 10 years, conformal radiation was replaced by IMRT, and the reason given was the new technology brought promises of better outcomes and fewer comorbidities. But what we saw in our study was that physicians adopted a new technology before there was a lot of evidence showing its effectiveness. IMRT seems to be better, but it was being used before the country really knew that.
“Now we are seeing a similar trend with proton therapy. Proton therapy is a type of radiation getting a lot of attention in the news, and physicians and patients are always interested in using new therapies that are more promising, but we don’t really know yet how effective it is.
“Until 2006 there were 3 proton centers in the United States; in the past 5 years that number has tripled, and an estimated 20 more centers are in the building or planning stages. These facilities cost on average $150 million to build and Medicare pays about $48 000 for each individual undergoing proton therapy; for IMRT, Medicare pays about $20 000.
“But we need to prove proton therapy is better than IMRT first before we think about costs. If proton therapy is better, and researchers prove it, then we can discuss cost—and maybe the costs will be justified.
“For patients with prostate cancer, they should talk with their physicians and ask if one therapy is better than another and ask to see the evidence. I’m not against proton therapy. We may ultimately prove it is better than IMRT, but we need more rigorous research to show that.”