Ezekiel J. Emanuel on health policy and other topics.

If you want to know what is wrong with American health care today, exhibit A might be the two new proton beam treatment facilities the Mayo Clinic has begun building, one in Minnesota, the other in Arizona, at a cost of more than $180 million dollars each. They are part of a medical arms race for proton beam machines, which could cost taxpayers billions of dollars for a treatment that, in many cases, appears to be no better than cheaper alternatives.

Proton beam therapy is a kind of radiation used to treat cancers. The particles are made of atomic nuclei rather than the usual X-rays, and theoretically can be focused more precisely on cancerous tissue, minimizing the danger to healthy tissue surrounding it. But the machines are tremendously expensive, requiring a particle accelerator encased in a football-field-size building with concrete walls. As a result, Medicare will pay around $50,000 for proton beam therapy for a patient with prostate cancer, roughly twice as much as it would if the patient received another type of radiation.

The higher price would be worth it if proton beam therapy cured more people or significantly reduced side effects. But there is no evidence showing that this is true, except for a handful of rare pediatric cancers, like brain and spinal cord cancer. For children, the treatment does a better job of limiting damage to normal brain cells and reducing the risk of cognitive impairment and hearing loss. But — fortunately — fewer than 3,500 American children get these cancers each year. It is impossible to keep all nine existing proton beam centers in full use, much less the approximately 20 others in planning or construction, with so few patients.

Jonathon Rosen

To generate sufficient revenue, proton beam facilities need to treat patients with other types of cancer. Consequently, they have been promoted for patients with lung, esophageal, breast, head and neck cancers. But the biggest target by far has been prostate cancer, diagnosed in nearly a quarter of a million men each year.

There is no convincing evidence that proton beam therapy is as good as — much less better than — cheaper types of radiation for any one of these cancers. There has not been a single randomized trial, only small, short-term studies. Such trials cannot evaluate the therapy’s long-term outcomes, nor resolve the concerns that some experts have raised regarding a potentially increased risk of hip fractures, bowel problems or other delayed effects associated with the therapy’s treatment for prostate cancer.

So why is the venerable Mayo Clinic building two proton beam facilities? Because it’s competing against Massachusetts General Hospital, M. D. Anderson in Texas, the University of Pennsylvania, Loma Linda in California — all of which have one. With Medicare reimbursement so generous, and patients and doctors eager for the latest technology, building new machines is sane, profitable business for hospitals like Mayo.

But it is crazy medicine and unsustainable public policy.

One solution is for Medicare to simply refuse to pay for proton beam treatment except for diseases where there is valid evidence that it is clinically superior, as many private insurers do. This would certainly help keep costs down, and it would also encourage manufacturers and researchers to actually conduct studies comparing proton beam therapy to other treatments.

However, it is often difficult to begin clinical trials without some reimbursement for the treatment that is being studied. So a second option is “coverage with evidence development.” In this approach, Medicare would pay for proton beam treatment for patients with prostate and other cancers, but only if the patients were enrolled in a randomized trial that would compare the outcomes of their treatment to those from surgery, other kinds of radiation or active surveillance. Medicare has used this approach sparingly, but it should be applied to more cases like this one.

The most promising option is a new approach called dynamic pricing. Medicare would pay more for proton beam therapy, but only for diseases that are proven to be treated more effectively by the therapy than by other forms of radiation. For cancers like prostate, it would pay only what it pays for the cheaper alternatives. But if studies were done showing that proton beam therapy was better than other treatments, the payment would go up. If no studies were done, or the new evidence demonstrated no advantages, then coverage would continue, but at the lower reimbursement.

Of course hospitals could continue charging patients more for proton beam therapy, and patients who wanted the treatment could pay the difference themselves. But this should not be seen as unfair to those who can’t afford it, because there are alternatives that are just as effective.

Everyone wants the best available care, especially for life-threatening diseases like cancer. But that doesn’t mean Americans should pay exorbitant costs for treatments that can’t be shown to be better than other, cheaper, options. If the United States is ever going to control our health care costs, we have to demand better evidence of effectiveness, and stop handing out taxpayer dollars with no questions asked.

Ezekiel J. Emanuel, an oncologist and former White House adviser, is a vice provost and professor at the University of Pennsylvania. Steven D. Pearson, a general internist, is the president of the Institute for Clinical and Economic Review at the Massachusetts General Hospital’s Institute for Technology Assessment.

A version of this article ran in print on January 3, 2012.