A Phase III trial led by researchers at The University of Texas MD Anderson Cancer Center has shown that intensity modulated proton therapy (IMPT) offers quality-of-life benefits over traditional intensity modulated radiation therapy (IMRT) in the treatment of oropharyngeal cancer. The trial's findings were presented at the 2024 American Society of Clinical Oncology (ASCO) annual meeting by Dr. Steven Frank, professor of Radiation Oncology and executive director of the Particle Therapy Institute at MD Anderson.

With a median follow-up of three years, the progression-free survival rates were similar between the two groups, with IMPT achieving 83% and IMRT achieving 83.5%, making IMPT statistically non-inferior to IMRT. Notably, IMPT resulted in a significant reduction in malnutrition and feeding-tube dependence. Specifically, 24% of patients undergoing IMPT sustained their nutrition with less than 5% weight loss, compared to 14% with IMRT. Additionally, feeding-tube dependence was reduced to 28% with IMPT, versus 42% with IMRT.

“The results of this multicenter Phase III randomized trial provide evidence for IMPT as a new standard-of-care treatment approach for the management of head and neck tumors,” said Frank. “This is significant for patients as it represents a curative, de-intensified option compared to traditional radiation therapy.”

Proton therapy, which utilizes protons instead of photons, offers biological and physical advantages by delivering radiation more precisely to the targeted area while limiting exposure to surrounding healthy tissues. This trial, the largest of its kind to date, enrolled 440 patients across 21 U.S. sites, with 219 receiving IMRT and 221 receiving IMPT. Patients were stratified based on human papillomavirus (HPV) status, smoking status, and prior chemotherapy.

While proton therapy was once primarily used to treat prostate cancer patients, a recent analysis from the National Association for Proton Therapy showed studies have led to proportional increases in applications for treating complex cancers beyond prostate, including breast, which rose from 1.7% to 9.2%; head and neck, from 5.9% to 14.5%; and gastrointestinal cancer, from 3.2% to 7%.

“Historically, large-scale trials confirming the benefits of proton therapy have been challenging due to limited patient access to proton therapy centers,” Frank noted. “Encouraging results like these demonstrate the benefits of proton therapy and hopefully help pave the way for increased access for patients in need.”

The study received funding from the National Institutes of Health (NIH) and the National Cancer Institute (NCI), as well as Hitachi. Dr. Frank disclosed proton-related grant funding from Hitachi and honoraria from Ion Beam Applications S.A. (IBA). Additionally, he has non-proton related associations with Boston Scientific, Affirmed Pharma, and C4 Imaging.

Rad Oncology Homepage