Advances in radiation therapy offer a new, more precise way to treat one of the most common cancers.
Prostate cancer is the one of the most common cancers in the United States; this year alone nearly 200,000 men will be diagnosed with the disease. Many of them will be treated with photon radiation therapy, in which x-rays or gamma rays are used to destroy the cancer cell’s DNA. But photon radiation doesn’t just stop at cancer cells. It passes through cancer cells and exits through normal healthy tissue.
In recent years, radiation therapy that uses protons instead of photons has emerged as an alternative. “The fundamental difference with proton therapy is that it has no exit dose into the surrounding tissues outside of the tumor target,” says Curtiland Deville, M.D., associate professor of Radiation Oncology and Molecular Radiation Sciences at Johns Hopkins University School of Medicine and associate director of the Johns Hopkins Proton Therapy Center. “That helps us to minimize the radiation doses going to other areas, which potentially helps to reduce the side effects of treatment.”
Protons vs. photons
Proton therapy isn’t new, but recent advances have made it much more precise, resulting in a surge of research and interest. As a result of this increased precision, proton therapy promises to be a much safer treatment. Unlike photons, protons have mass and thus do not travel infinitely.
“What you have today with proton radiation therapy is spot-scanning,” explains Dr. Deville. “You have a target, you break it up into little spots, and those spots are painted in layers. If the old proton therapy technique was like using a spray can, this is like using a fine paintbrush — you can really sculpt and tailor that dose and treat more complex targets.” For prostate cancer, this allows us to treat more complicated targets like high-risk and post-operative prostate cancer.
That means the exit dose — and potential associated damage and complications — can be much less. Studies have indicated that patients treated with proton therapy can experience fewer severe side effects.
That potential is being used to treat patients in new facilities like the new Johns Hopkins Proton Therapy Center at Sibley Memorial Hospital in Washington, D.C. Here, the cutting-edge nature of this therapy is apparent in their state-of-the-art proton therapy center that combines the unsurpassed expertise of Johns Hopkins specialists, innovative technology and advancements in research to provide tailored cancer treatments for children and adult
It’s important to note that the full potential of proton therapy is still being developed.
The Johns Hopkins Proton Therapy Center is involved in developing the evidence supporting expanded use of proton therapy for prostate cancer through its world class research program and scientists. They maintain an anonymous research registry of treatment data to better understand which cancer patients will benefit from it.
Multidisciplinary clinics, like the multidisciplinary prostate cancer clinic at the Johns Hopkins Kimmel Cancer Center at Sibley, bring together medical, surgical, and radiation oncologists, radiologists, pathologists, and other healthcare providers who can holistically assess a patient’s complex needs for treatment, including clinical trials. Because the proton therapy center is located at Sibley, it is a convenient treatment option for this clinic.
Dr. Deville stresses that multidisciplinary clinics like Johns Hopkins are the best option for cancer patients. “There’s good data that multidisciplinary clinics result in better outcomes for people with cancer. Everyone is very different; people can come in and see all the providers at one time and come up with a consensus opinion about treatment.”
Proton therapy benefits
“In general, when we use proton therapy, we’re trying to reduce the side effect profile of treatment, enhancing the therapeutic ratio,” Dr. Deville says. If proton therapy is more expensive on the front end, fewer side effects could also mean fewer hospitalizations or interventions, reducing the overall cost of care.
As research continues, the potential for proton therapy to reduce side effects and improve outcomes may soon make prostate cancer much easier — and safer — to treat.