The costly form of radiation therapy that has become the norm for prostate cancer in the United States may be no better than the older, cheaper variety -- at least for some men, a new study suggests.
Researchers found that among more than 1,000 U.S. men who had radiation therapy after prostate cancer surgery, the newer form -- known as intensity-modulated radiotherapy (IMRT) -- had no advantage over the conventional version.
Men who received IMRT were no less likely to be treated for a prostate cancer recurrence over the next few years. And their rates of long-term side effects -- such as urinary incontinence and erectile dysfunction -- were no lower.
But the findings, reported online May 20 in JAMA Internal Medicine, will not spell the doom of IMRT. One reason is, the vast majority of U.S. men who receive radiation for prostate cancer are already given IMRT.
"I don't think this is going to change practice," said Dr. Matthew Cooperberg, a urologist at the University of California, San Francisco, who wrote an editorial published with the study.
But he said the findings do beg the question of why IMRT is reimbursed at such a high rate. A 2011 study in the Journal of Clinical Oncology found that Medicare paid out an average of nearly $11,000 more for IMRT, versus the older radiation therapy (called conformal radiotherapy).
"We need a reimbursement system that rewards outcomes instead of technology," Cooperberg said.
Still, Dr. Ronald Chen, one of the researchers on the new study, said the findings apply to a specific group of patients who receive IMRT: men who have it after prostate cancer surgery -- either to help prevent a recurrence or to treat one.
There are other patients who receive radiation as their initial therapy, explained Chen, an assistant professor of radiation oncology at the University of North Carolina at Chapel Hill.
And in a study published last year in the Journal of the American Medical Association, Chen and his colleagues found that for those men, IMRT does carry a lower risk of certain side effects than conformal radiotherapy. It also showed a somewhat lower risk of cancer recurrence.
"I think the question is, when is the new technology helpful, and when is it not?" Chen said. "We need to be smart about how we use technology."
The new findings suggest that when it comes to radiation given after surgery, "newer" does not mean "better."
The IMRT technique was designed to minimize damage to healthy tissue around the tumor. Doctors use 3-D computer images to visualize the area, then target it with thin radiation beams from different angles -- with the individual beams varied in intensity.
IMRT has exploded in the United States in the last decade or so. In 2000, it was barely a blip on the radar, but by 2008 it accounted for 96 percent of all external radiation treatments for prostate cancer, according to the editorial. (Men can also have an internal form of radiation, where radioactive "seeds" are implanted in the prostate gland.)
Why did the technology take off? Cooperberg said IMRT was heavily marketed, and the procedures were also reimbursed at a much higher rate -- a potential incentive to some.
Plus, Cooperberg said, "Hospitals generally want to be seen as cutting-edge, and patients often want the latest and greatest thing."
Chen agreed. "Oftentimes in this country, doctors and patients chase after the newest technology, believing that it must be better -- even before the evidence is in."
But although IMRT is now dominant, Chen said he thinks "there's a chance for a reversal." If the older conformal radiotherapy is just as good for men who've had prostate cancer surgery, then using it would bring down the costs of radiation for those patients.
And that might allow more men to get it, according to Chen. He said that right now, radiation is "underused" in men who might benefit from it after prostate surgery, and costs may be one reason.
The new findings are based on Medicare claims for 457 men who underwent IMRT between 2002 and 2007, and 557 men who had conformal radiation therapy. Chen's team followed their outcomes through 2009.
Overall, there were no major differences in the men's risk of side effects: About 15 percent of those who'd received IMRT were diagnosed with erectile dysfunction, compared with 12 percent of men who'd received the older radiation therapy, for example.
When it came to the cancer itself, just over 8 percent of IMRT patients needed additional therapy during the study, versus 7 percent of conformal radiotherapy patients.
Dr. James Yu, an assistant professor of therapeutic radiology at Yale School of Medicine, said the study was well done.
It "provides an important piece of the puzzle for evaluating this important but costly technology," Yu said.
There are still questions, though, he added. It's possible, for example, that IMRT could have an advantage when it comes to men's ultimate cure rates, or their overall quality of life over time.
Cooperberg said Medicare claims are an imperfect way to gauge quality of life. Yu agreed that claims data may not capture all the ways treatment can affect men's lives, such as their sexual function other than an official diagnosis of erectile dysfunction.
IMRT is not, however, the latest radiation technique out there. That would be proton beam therapy, which is supposed to be even more targeted than IMRT -- and is twice as expensive. But so far, research has suggested the newer technology is no better.
"There's not a shred of evidence that it's better than IMRT," Cooperberg said.