Proton Therapy Overhyped for Prostate Cancer?

Gerald Chodak, MD


January 30, 2013

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Hello. I am Dr. Gerald Chodak for Medscape. In this report, I want to talk about proton radiation for prostate cancer. This is prompted by several things: first, radio advertisements I personally heard for a facility in Illinois claiming fewer complications with the use of proton radiation treatment (PRT) for prostate cancer; second, a Wall Street Journal article[1] citing a study by Yu and colleagues[2] in the Journal of the National Cancer Institute several months ago; and last, by a relatively recent report[3] that the Oregon Health Systems has decided not to purchase or build a proton facility despite many centers going up around the United States.

The controversy continues. The claims are clear. PRT is supposed to be able to focus the beams more tightly and thereby reduce complication rates. Is there any evidence for that? Absolutely not. In fact, if we look at several reports from SEER (Surveillance Epidemiology and End Results)[4] or from Medicare beneficiaries, particularly the recent report by Yu and colleagues,[2] we see that [this procedure results in] some reduction in the urinary complaints at 6 months, but this goes away by 12 months, and there is no difference in gastrointestinal toxicity when compared with patients who undergo intensity-modulated radiation therapy (IMRT). Another report[5] that has been in the literature from the SEER database shows higher morbidity from patients receiving PRT.

Now, the difficulty with all of these comparisons is obvious: they are retrospective reviews and are based on Medicare claims or SEER-based claims; therefore, the results do not include the possible side effects or complications that do not prompt medical attention [and therefore would not be reported to] the Medicare or SEER database.

The other problem is that these reports do not control for differences in technique, age of population, or comorbidities, although Yu and colleagues reported that the patients getting PRT were younger, had fewer comorbidities, and were less likely to receive hormone therapy. Also, patients who get IMRT often have their lymph nodes radiated. Each of these factors could contribute to some of the difference [in outcomes for PRT vs IMRT] seen at 6 months but not at 12 months. The bottom line is that long term, there is no evidence that PRT results in better outcomes.

In addition, we have yet to see a single report talking about long-term mortality. The people at Loma Linda [University Medical Center] have been using PRT for enough years to provide information about what happens to patients long-term. Looking at PSA (prostate specific antigen) control is a completely inadequate way to assess the effects of radiation therapy because it does not predict long-term outcomes.

The bottom line, once again, is that PRT is a technology that is at least 30% more costly than IMRT, with no clear evidence that it does reduce long-term side effects, and absolutely no data to show that it provides better outcomes. Yet the government continues to pay more money for it. I read an analysis that shows the extra expenditure from PRT could reach $100 million/year. It will cost $15 million to do a prospective randomized trial, which is underway at Massachusetts General Hospital and University of Pennsylvania.

Until [we see those results], what should we do? First, any advertisements promoting lower morbidity from PRT should be removed from the air; they are not supported by evidence-based information. Second, for men who are being counseled about PRT, it should be made clear that at this time, there is no evidence of a benefit either in terms of side effects or cancer control.

At the end of the day, we continue to be faced with the same recurring dilemma: New technologies appear and are reimbursed without the need to prove that they are truly benefitting patients and worth the added cost.

I hope this will change at some time in the future and help to stop our runaway medical expenses. I look forward to your comments. Thank you.