Proton therapy got positive billing at the recent Particle Therapy Cooperative Group, as researchers from across the country presented findings that showed proton therapy reduced potentially life-altering side effects and improved survival rates for cancer patients.
The National Association for Proton Therapy (NAPT) released a summary of the results, which included the findings of studies focused on esophageal, prostate and breast cancer.
Proton therapy reduces radiation’s secondary effects in esophageal cancer
Three institutions—M.D. Anderson Cancer Center, the Mayo Clinic and the University of Maryland—partnered to conduct the study on esophageal cancer patients. The research focused on older esophageal cancer patients treated with three types of radiation: 3-D conformal, Intensity Modulated Radiation Therapy (or IMRT) and proton therapy.
The results showed “fewer postoperative heart and lung complications such as acute respiratory distress syndrome and heart attacks, shorter hospital stays and reduced risk of postoperative death” in patients treated with proton therapy versus the conventional radiation, according to the NAPT report.
“Cancer of the esophagus is a difficult diagnosis that ideally is treated with radiation and chemotherapy followed by surgery,” said Dr. Ben Wilkinson, radiation oncologist and medical director for Provision CARES Proton Therapy Center. “This study emphasizes that reducing unneeded radiation dose to the lungs and heart by using proton therapy leads to fewer side effects including less lung inflammation and fewer heart attacks. This is critical information for any physician treating esophageal cancer and for any family who is going through a diagnosis of esophageal cancer.”
Prostate cancer patients see longer life with protons
A pair of presentations at the PTCOG conference emphasized the benefits of proton therapy for prostate cancer patients.
The first study was conducted by Northwestern Medicine Chicago Proton Center and the University of Florida Health Proton Therapy Institute, utilizing results from the major Surveillance, Epidemiology & End Results Registry of the National Cancer Institute. The results showed patients treated with proton therapy had a significantly higher five-year survival rate than patients treated with IMRT. They also experienced fewer side effects including bladder complications and secondary, radiation-induced cancer.
“The data presented by Northwestern University shows that reducing radiation dose matters. With IMRT, there is unneeded radiation that is given to the bladder and bowel that, in this study, leads to an increase in side effects and treatment-related cancers,” Wilkinson said.
The second presentation came from the work of the doctors at the University of Florida Health Proton Therapy Institute and Mayo Clinic in Arizona. Their work showed that while patients treated with IMRT versus protons experienced similar rates of complication, their ability to control the disease with proton therapy in patients with low- and intermediate-risk cancers was significantly higher than with conventional radiation.
“For the first time, we see an increase in survival for patients treated with proton therapy,” Wilkinson said. “These data need to be confirmed but are an exciting step forward for patients who are seeking the best treatment with the fewest side effects.”
Short-course proton therapy effective for breast cancer
Working with several institutions the Proton Collaborative Group conducted a study of patients with early-stage breast cancer who received partial breast short-course, or hypofractionated, proton therapy treatments in which a tumor site is treated with a smaller number of high-intensity treatments instead of a traditional longer and more frequent treatment protocol.
The research showed proton therapy treatment worked as effectively with these patients as the longer regimen. Additionally, patients did not experience significant side effects or cosmetic issues with the hypofractionated course. All patients continue to be in remission.
“It’s remarkable that the reported studies agree pretty well with each other,” said Niek Schreuder, Provision CARES Proton Therapy Center vice president and chief medical physicist. “The SEER data is totally independent from the University of Florida studies, but they agree well with each other. The study refutes any of the previous SEER based studies that was very biased in many regards. The interesting thing is that what are reported here is just a small snapshot of the real data that will be published soon.
“It’s powerful and should serve us well in the quest for getting proton treatments approved by private insurance,” Schreuder added.