A Phase III trial led by researchers at The University of Texas MD Anderson Cancer Center compared intensity modulated proton therapy (IMPT) to traditional intensity modulated radiation therapy (IMRT) as part of chemoradiation treatment for patients with oropharyngeal cancer. The results were presented at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting, with IMPT achieving similar clinical outcomes and significant patient benefits compared to IMRT. The progression-free survival (PFS) rate at three years was 83% for IMPT and 83.5% for IMRT, with IMPT deemed statistically non-inferior. Patients receiving IMPT experienced reduced malnutrition and feeding-tube dependence compared to those receiving IMRT.
Lead researcher, Steven Frank, described the results of the trial as evidence for IMPT as a new standard-of-care treatment for head and neck tumors, offering a curative, de-intensified option compared to traditional radiation therapy. Proton therapy has biological and physical advantages over photon-based radiation, allowing for more targeted delivery of radiation to the tumor site while limiting exposure to nearby normal tissues. This trial is the largest randomized Phase III trial to date investigating proton therapy in comparison to traditional radiation, with 440 patients enrolled at 21 sites in the U.S. and stratified based on HPV status, smoking status, and prior chemotherapy.
Historically, large-scale trials to confirm the benefits of proton therapy have been challenging due to limited access to proton therapy centers for patients. However, the encouraging results from this study demonstrate the benefits of proton therapy and may pave the way for increased access to this treatment option for patients in need. The study was funded by grants from the National Institutes of Health (NIH)/National Cancer Institute (NCI) and Hitachi, with Frank disclosing proton-related grant funding from Hitachi and non-proton related healthcare relationships with other companies.
Overall, the trial findings demonstrate the potential of IMPT as a new standard-of-care treatment approach for patients with head and neck tumors, offering comparable clinical outcomes to IMRT with added patient benefits in terms of reduced malnutrition and feeding-tube dependence. Proton therapy’s ability to deliver radiation more precisely to the tumor site while sparing nearby normal tissues makes it an attractive option for patients undergoing chemoradiation treatment. With increasing recognition of the benefits of proton therapy, efforts to improve access to this technology for patients in need are likely to increase in the future.