The Promise of Proton-Beam Therapy

A radiation therapist at M.D. Anderson moves Glaros into position. The rotating device above him, which is connected to a particle accelerator, will fire protons at his tumor.

Competition for precious treatment slots isn't the only obstacle that patients face in getting proton therapy. Many must travel hundreds or thousands of miles and stay near a treatment center for weeks while receiving brief daily doses of radiation. Glaros and his parents, for example, came 781 miles from their home in Overland Park, Kan., for treatment in Houston for the tumor that began as an excruciating pain in his hip and has now spread to his lungs. He isn't supposed to miss even a day of treatment, his mother says, so getting home to apply for his driver's license has morphed into a logistical nightmare.

The dearth of proton facilities is largely due to their high upfront cost. It can easily take $100 million or more to construct the football field-size building needed to house a particle accelerator, the multistory rotating machinery that surrounds each treatment chamber, and heavy concrete shielding walls. The huge price tag means institutions that offer proton beam therapy have often had to go through financial contortions to do so. M.D. Anderson, for example, had originally sought to own its proton center outright and wanted to run it as a nonprofit. When the University of Texas didn't come through with the money, however, planners turned to a consortium of private investors instead.

Such financial realities can put undue pressure on doctors to treat prostate cancer cases, which are relatively simple and quick—and therefore most profitable. Treating a child with cancer, in contrast, can tie up a facility for three or four times as long, adding to the patient bottleneck and slowing an indebted center's ability to repay its loans. "There's definitely pressure from a few of the investors to treat only prostate cancer," acknowledges James Cox, the top radiation oncologist at M.D. Anderson's proton center. Adds Allan Thornton, the medical director at the Midwest Proton Radiotherapy Institute in Bloomington, Ind.: "I've got people breathing down my neck who want to make money on this place." He aims to make prostate cancer about 30 percent of the cases at his institution; Cox, 50 percent at his.

Nevertheless, hospitals say demand for proton beam therapy is ballooning, driven in large part by the huge number of prostate cancer diagnoses—about 186,320 a year—and the favorable impression many prostate patients have of the therapy. Loma Linda, which has been using protons to treat men with prostate cancer since 1991, has published promising results. One study, for example, found major rectal and urinary side effects among less than 1 percent of Loma Linda patients; it didn't specify rates of sexual side effects. Those types of problems are risks associated with other radiation treatments or surgery.

Some men who have received protons at Loma Linda have been so thrilled with their experience that they've become among the technology's biggest boosters, spreading the word through books, chat rooms, support groups—even PowerPoint presentations at churches and clubs. One Loma Linda patient, Robert Marckini, founded what's now a 3,340-member proton therapy support group, the Brotherhood of the Balloon, that has been instrumental in increasing awareness of the technology among prostate patients. "Almost every one of [the members] learned about proton beam therapy from another patient," he says, not from a doctor.

But certain doctors—not to mention the occasional patient who has experienced side effects from proton therapy—wonder whether the high-tech allure of protons hasn't outpaced the science. "Because of Internet buzz, the morbidity associated with proton beam therapy is underappreciated," says Anthony Zietman, a radiation oncologist at Mass General who specializes in prostate cancer. Many of his patients, he says, are surprised to learn that proton beam therapy exposes the bladder and rectum to high doses of radiation and does, in fact, carry a significant risk of causing impotence. Although preliminary research has suggested protons may be superior to conventional radiation for prostate cancer, there's a lack of randomized studies (the type doctors consider most rigorous) comparing the two—and standard radiation techniques are improving all the time.