Proton Therapy Appears to Be Less Cost-Effective

An analysis of Medicare records shows that proton radiotherapy (PRT) for prostate cancer is reimbursed at about 1.75 times the price of conventional intensity-modulated radiotherapy (IMRT) but provides patients no decrease in toxicity at 12 months, according to an article published in the Journal of the National Cancer Institute.

PRT systems are growing in popularity, in part because proton radiation is hypothesized to lower toxicity for patients. The X-ray beams used in IMRT can cause damage on their entire path through the body—not just in the tumor—which can lead to side effects. However, protons mainly release their damaging energy where they stop and do not release energy past the tumor. “It's like a depth charge,” says James Yu, MD, lead author on the article and assistant professor of therapeutic radiology at the Yale University School of Medicine in New Haven, CT. This level of control is particularly promising for treating prostate tumors because the target tissue is near the rectum and the bladder.

PRT has greater capital costs because the equipment needed to energize protons is larger and more expensive than the X-ray sources used for IMRT. To make up for these expenses, Medicare pays more for the procedure. Yu and his colleagues evaluated the Medicare records of 27,647 men treated for prostate cancer. About 98% of the men received IMRT at a median reimbursement of $18,575; 2% were treated with PRT, for which Medicare gave a median reimbursement of $32,428.

The Yale researchers looked for subsequent claims related to radiation toxicity, such as cautery for rectal bleeding. PRT was associated with a transient reduction in toxicity. At 6 months, the records of 5.9% of men treated with PRT showed claims related to genitourinary toxicity, compared with 9.5% of those treated with IMRT. However, at 12 months, there was no difference. No differences in gastrointestinal toxicity or other adverse effects were seen at either 6 or 12 months.

In practice, PRT does not seem to spare healthy tissue around the prostate, says Yu. Given patient movement and other factors, it's difficult to precisely target the tumor and only the tumor.

“Patients and doctors have a tendency to be drawn to new technology and treatments, even when they haven't been proven to be better,” comments Ronald Chen, MD, MPH, assistant professor of radiation oncology at the University of North Carolina in Chapel Hill.

The Yale study, which revealed that many patients incurred the cost of traveling long distances for daily PRT treatments over 7 or more weeks, has some limitations. Because the study was retrospective, it only detected side effects that led to Medicare claims. The retrospective data will soon be complemented by results from a randomized clinical trial comparing IMRT and PRT for prostate cancer that is now recruiting patients. That trial will be jointly run by investigators at the University of Pennsylvania Perelman School of Medicine and the Massachusetts General Hospital Cancer Center in Boston.