Nuclear Particle Accelerators the New Rage in US, but Efficacy Questionable

Nuclear particle accelerators are the latest rage in the US in the fight against cancer. But some point to the huge cost involved and also question their efficacy vis a vis X-rays.

The machines accelerate protons to nearly the speed of light and shoot them into tumors. Scientists say proton beams are more precise than the X-rays now typically used for radiation therapy, meaning fewer side effects from stray radiation and, possibly, a higher cure rate.

X-rays, which are high-energy electromagnetic waves, pass through the body, depositing their energy all along the way, not just in the tumor. By contrast, protons — subatomic particles with a positive electrical charge — can be made to stop on the tumor and dump most of their payload there.

Tumors in or near the eye, for instance, can be eradicated by protons without destroying vision or irradiating the brain. Protons are also valuable for treating tumors in brains, necks and spines, and tumors in children, who are especially sensitive to the side effects of radiation.

But then a 222-ton accelerator — and a building the size of a football field with walls up to 18-feet thick in which to house it — can cost more than $100 million. That makes a proton center, in the words of one equipment vendor, “the world’s most expensive and complex medical device.”

Also while protons were vital in treating certain rare tumors, they were little better than the latest X-ray technology in dealing with prostate cancer, the common disease that many proton centers are counting on for business.

“You can scarcely tell the difference between them except in price,” insists Dr. Anthony L. Zietman, a radiation oncologist at Harvard and Massachusetts General Hospital.

But the race has begun, as it were. Until 2000, the United States had only one hospital-based proton therapy center. Now there are five, with more than a dozen others announced. Still more are under consideration.

“I’m fascinated and horrified by the way it’s developing,” said Zeitman. “This is the dark side of American medicine.”

Once hospitals have made such a huge investment, he points out, doctors will be under pressure to guide patients toward proton therapy when a less costly alternative might suffice.

Similar cost concerns were expressed in the past about other new technology like M.R.I. scanners. While those have become accepted staples of medical practice, there is still concern about their overuse and the impact on medical spending.

Companies have sprung up to help finance, build and operate the proton centers. In some cases, local and state governments, seeking to attract medical tourists, have chipped in. Such financing is allowing proton centers to be built by community hospitals or groups

Proponents say that more than 800,000 Americans — representing nearly two-thirds of new cancer cases — undergo radiation therapy each year. If only 250,000 of them could benefit from protons, they would fill more than 100 centers.

“There are no solid clinical data that protons are better” said Dr. Theodore S. Lawrence, the chairman of radiation oncology at the University of Michigan. “If you are going to spend a lot more money, you want to make sure the patient can detect an improvement, not just a theoretical improvement.”

An economic analysis by researchers at Fox Chase Cancer Center in Philadelphia found that proton treatment would be cost-effective for only a small subset of prostate cancer patients, reports The New York Times.

Lack of data aside, men are flocking to proton treatment.

“I’m 67 years old, and the last thing I want to do is wear a diaper for the rest of my life,” said Pete Freeman of Spokane, Washington, who is undergoing the treatment now at Loma Linda in California.

Prostate cancer treatment there requires about two months of daily sessions. The actual irradiation, which the patient does not feel, takes only about a minute. Most men with early prostate cancer have no symptoms from their disease and many say the treatment has few immediate side effects, other than fatigue and an urgency to urinate.

“We go have our treatments, and we go out and play golf,” said Harold J. Phillips, an accountant from Tacoma who was being treated recently at Loma Linda.

Doctors are also learning how to use protons to treat lung and breast cancer. And over time, doctors say, costs should come down as the technology improves and it becomes more routine to build and operate proton centers. One company is trying to develop a $20 million proton system and has received orders from several hospitals.

On the horizon is therapy using beams of carbon ions, which are said to be even more powerful in killing tumors. Touro University says it will build a combined proton and carbon therapy center outside San Francisco, to open as early as 2011. The Mayo Clinic is also seriously considering one. Such centers will cost even more — as much as $300 million.

Source-Medindia
GPL/M