ASTRO 2014: Proton therapy's lightspeed promise

As the American Society for Radiation Oncology (ASTRO) concludes today at the Moscone Center in San Francisco, Molecular Imaging caught up with two experts in proton therapy technology and policy—David C. Beyer, MD, president-elect of ASTRO, and Sameer R. Keole, MD, vice chair of ASTRO’s government relations council and a radiation oncologist at the Mayo Clinic in Phoenix—to talk about how this cutting-edge technology is changing. Some of the covered topics include advancement of clinical trials, scalability of the technology, innovative image guidance and the emergence of an appropriate use model.

Proton therapy was approved for use as a treatment of cancer in the late 1980s and was fully covered by the Centers for Medicare & Medicaid Services (CMS) for select applications in so-called eloquent areas of anatomy by the late 1980s. What is different today is the sheer enormity of data that has been amassed and that continues to develop, and specifically comparison data between X-ray-based therapy and protons that show how proton systems are as effective, if not superior, to X-ray technologies for treating certain cancers.

“I don’t practice in a center that does not have protons,” Beyer insisted. Some of the applications for proton therapy that are gaining a lot of support across the industry include pediatric cancers, melanoma of the eye and some blood cancers. “Those are things that we believe there is some potential, either because we are able to give more radiation and cure more patients or [are] able to give less radiation. We believe that these should be covered.”

Other clinical applications that have already made strides include prostate and lung cancers, head and neck cancers and sarcomas. We are starting to see the answers we need, said Keole, but the discovery needs to continue in order to determine definitively how much better proton therapy is than X-ray for a range of tumors.

“We now have some very impressive clinical data,” said Keole. “Up until this point a lot of the data has been theoretical, but now we are starting to see the difference between X-rays and protons.”

Scaling things down in both size and price

Another major improvement in proton therapy is a reduction in cost and scalability of design. Where a full-blown proton center serving several treatment rooms might cost $100 million to build, today there are single-room strategies that can cut those costs by three quarters, to $25 million. This option could be the optimal choice for mid-range radiation oncology institutions in metropolitan cities.

The first of these junior proton centers to get installed went to Washington University in St. Louis. Another single-room center with pencil-beam scanning and on-board cone-beam CT guidance has been installed at the Willis-Knighton Cancer Center in Shreveport, La. Other systems have been in the works over the past year, including a single-room system in Japan.

“Before one was installed at Washington University, it was something that everyone thought was unimaginable,” explained Beyer. “Now they are up and running and treating patients.”

For larger clinics, multiroom designs are still the desired option. Such centers are in the process of installation at the Mayo Clinics in both Rochester, Minn., and in Phoenix.

“Proton therapy is now becoming attainable in medium-sized markets,” said Keole. “Not everybody can travel to Harvard or MD Anderson.”

Even so, careful study of health outcomes must precede any proliferation of technology, especially one with such a price tag, but now seems like the age of proton therapy with many clinical trials already completed and in the works.

“We want to give proton therapy a fair shake,” said Keole. “We have a window and it is very important that we all work together and provide proof of the benefits of proton therapy from institutions that deliver care, the national research institutions and the insurers, to continue to support clinical trials that are testing the value of proton therapy.”

Some of the perks of the new systems being installed in the past few years are state-of-the-art detectors and cone-beam CT volumetric imaging like the one in the Willis-Knighton Cancer Center in Louisiana. Keole estimated that this will become industry standard within five to 10 years.

Appropriate use of protons

ASTRO just recently put out a model policy on proton therapy to guide appropriate use across institutions. Areas where proton therapy has absolute reign and should be supported 100 percent by not just CMS but private insurers is ocular tumors and melanomas and tumors that are wrapped around the spinal cord and other eloquent areas of anatomy. But the clinical benefit is scattered far and wide beyond these conventional applications. What is needed, both Beyer and Keole agreed, is coverage with evidence development across the board.

“We want more science to study what’s going to be better for our patients,” said Keole.

More phase III clinical trials are necessary in order to pull together more comprehensive data. A lot of phase II and some phase III data exist, but researchers need more to drive it home for better reimbursement across private insurers.

“So much of what we do is driven by reimbursement,” added Beyer. “If treatment X is not covered, we have to rethink what we do.”

Struggling for reimbursement in the private sector

CMS covers proton therapy rather liberally for those who are eligible. The problem is with private insurers that often deem proton therapy as an experimental therapy. But a therapy that was approved in the 1980s and reimbursed by CMS by the 1990s is well established, said Keole. This is more a semantic game that insurers can play—a loophole that keeps them from being obligated to proton centers and patients. Even those insurers who do reimburse for proton therapy may stagger coverage levels between several plans.

“There are incredible variations between companies,” added Beyer. “And even within companies. You can get the top of the line plans and the bare-bones plans. There is pretty wide variation. Some may even cover inpatient care but not outpatient care. We have a messy system and some people like it that way.”

This is why compiling solid health outcomes for proton therapy is so important.  

“This is an area that has started off slow,” said Beyer. “For many years there were only two proton centers in the U.S., but we are starting to see this technology develop.”

It is also getting cheaper, which will provide added incentive to insurers to reimburse proton procedures more in the line of linear accelerator treatments, noted Beyer. Proton systems probably will never replace linear accelerators, but they are set to become a more integrated instrument in radiological practice. Proton therapy still accounts for only a minute portion of all radiation treatments. A cheaper price tag will do much to improve the adoption of this technology.

“There is no question in my mind that we will find that it becomes more affordable,” said Beyer. “It happens with everything. Just look at computer technology. Proton technology is big and complex and involves advanced physics and qualified people to operate these systems. It will always be a higher-end type of treatment at higher-end value.”