Despite the considerable costs and specific-use controversies (especially regarding prostate cancer), proton beam radiation therapy (PBRT) remains a much sought-after technology for certain cancer centers, as well as some institutions that don't even have any direct health care affiliations.
PROTON BEAM RT...
Image ToolsAs reported in Part 3 of this series in the April 25th issue, the current PBRT club consists of only seven members providing clinical care with a few other facilities either already under construction or being considered so for the future, often depending more on financing than medical science.
OT requested interviews over several weeks from various institutions to discuss how PBRT was being utilized in today's competitive health care environment
Interestingly some of those centers without the technology declined to discuss the matter at all, as did the granddaddy of proton therapy centers, Loma Linda University Medical Center.
For example, after learning from several sources about a proposed consortium among several prominent academic cancer centers in New York City, I hoped to speak with Simon N. Powell, MD, PhD, Chair of the Department of Radiation Oncology at Memorial Sloan-Kettering Cancer Center (MSKCC), to learn more about the concept—which seemed to be a very cost-effective and collegial attempt at making this expensive technology available to more patients without any single institution incurring the crushing costs—as well as to find out where MSKCC might refer its patients who could benefit from proton therapy.
Via the Cancer Center's Public Affairs Office, though, Dr. Powell declined to be interviewed, saying that it was too early and premature to discuss either PBRT or the consortium.
JAMES D. COX, MD Pro...
Image ToolsDr. Powell's counterpart at Roswell Park Cancer Institute, Michael R. Kuettel, MD, PhD, MBA, President of the American College of Radiation Oncology (ACRO), also declined, replying through Public Affairs that he was not an expert on proton beam radiation therapy and that any questions regarding ACRO's position would have to be submitted in writing for review by the association's board.
Johns Hopkins Cancer Center said it would not refer any prostate cancer patients for proton therapy, but did send some pediatric sarcoma patients to Massachusetts General Hospital for a specific clinical trial.
I called Jerry D. Slater, MD, Professor and Chairman of the Department of Radiation at Loma Linda, home of the James M. Slater, MD, Proton Treatment and Research Center, named for his father, and operating since 1990. I was told that Dr. Slater was unreachable until more than week after this article was to be submitted, and then asked the public affairs department for another expert. They insisted on a list of specific questions, which I sent, but no one followed up by the deadline.
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Baby & Bath Water
In the PBRT article in the April 25th OT, Anthony L. Zietman, MBBS, MD, President of the American Society for Radiation Oncology and the Jenot and William Shipley Professor of Radiation Oncology at Harvard Medical School and Director of the Radiation Oncology Residency Program at Massachusetts General Hospital, commented that he was “afraid that the prostate issue will cause proton therapy to be discredited and the baby will be thrown out with the bath water.”
He was referring to the lack of any clinical evidence that proton therapy was better than some other more readily available radiation therapies for prostate cancer, and that some centers were treating men for prostate cancer because it was easier and more lucrative and they could handle up to six men in the same time it took to treat a single pediatric patient under anesthesia, a much better candidate for PBRT.
Dr. Zietman also said that as soon as its $10 million NCI grant was approved, Mass General and the University of Pennsylvania Cancer Center would immediately begin a collaborative randomized clinical trial comparing PBRT with intensity modulated radiation therapy (IMRT) for prostate cancer, with quality of life as the endpoint.
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‘Very Complicated Question’
Jay S. Loeffler, MD, Chair of Radiation Oncology at Mass General, and the Herman and Joan Suit Professor of Radiation Oncology at Harvard Medical School, called discussing the use of PBRT “a very complicated question—It shouldn't be, but it is,” he said.
“Protons produce a better dose distribution compared with x-rays, so if you take the fanciest x-ray dose, then protons are always superior to them. The problem in the field of proton therapy is that there has never been a randomized trial comparing the best of x-rays with the best of protons. Radiation oncology is a funny field because we make decisions about treatment delivery based on computer-graphics and a summation of the dose distribution and we adopt new technologies based on improvement of dose distribution.”
JAY S. LOEFFLER, MD ...
Image ToolsHe noted that the FDA requires clinical trials for drug development to show how safe the drug is and how it compares with other available drugs, and that a comparable system does not exist in radiation oncology. “If you have a new technology where the dose distribution is better than other technologies, we assume that it provides better therapy—and it might, but there's no evidence to support it.”
He added that many people would now argue that proton therapy will be obviously superior in children because the amount of radiation outside the target volume is reduced, a situation that also reduces the potential late effects in a developing child such as organ function, growth, and risk of second tumors.
“In the pediatric world there is very little debate that protons are a technology that should be associated with better long-term outcomes, but you need about 20 or 30 years of outcomes to prove that.
“There are also subsets of tumors of the eye where proton therapy appears better than any other radiation technology—particularly ocular melanomas where patients can have tumors controlled and can keep useful vision, which would not be feasible if more common types of radiation were used.”
And Dr. Loeffler said there is also little argument that patients with certain tumors of the skull base that require enormous controlled doses of radiation would also be better off if treated with protons.
However, he noted that where proton therapy “gets fuzzy” is in treating prostate cancer: “We have not turned this place into a prostate cancer treatment factory like some other proton centers have. We treat selective patients on protocol asking questions, but we certainly don't routinely offer all our prostate cancer patients proton therapy.”
Dr. Loeffler said that there was also an issue when treating an elderly group of prostate cancer patients who might not have the life span to prove that decreasing the dose outside the prostate makes a substantial difference.
“It might, but we may never be able to prove that, and I think that while we might find that protons are the standard of care for the cancers I've mentioned, we are more dedicated to quantifying the potential gain by designing studies to document potential proven outcomes of protons versus x-rays.”
He said that in addition to the proposed randomized clinical trial for prostate cancer with Penn, Mass General was involved in another trial in collaboration with M.D. Anderson that was looking at lung, liver, head and neck, and a variety of pediatric cancers.
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