New Lancet Phase III Study Shows Proton Therapy Significantly Improves Survival and Reduces Toxicity in Head and Neck Cancers - Marking a Breakthrough in Advanced Cancer Care

• Ten percent higher 5-year overall survival rates in patients receiving precise proton therapy vs. traditional radiation therapy
• Patients had significantly fewer side effects and improved quality of life, including less feeding tube dependence, less dry mouth, better swallowing, improved work productivity, and less immune system suppression
• Led by researchers at the University of Texas MD Anderson Cancer Center, this multi-institutional, consortium-driven, comparative study is the largest of its kind and the first to demonstrate a survival benefit for proton therapy
• NAPT calls for immediate access to proton therapy for appropriate patients

JACKSONVILLE, Fla., Dec. 11, 2025 /PRNewswire/ -- A new study published today in The Lancet showed results from the largest of its kind Phase III trial demonstrating a significant survival benefit for patients with oropharyngeal cancers who were treated with proton therapy compared to traditional radiation therapy. Led by researchers at the University of Texas MD Anderson Cancer Center, this multi-institutional comparative study enrolled patients at 21 institutions across the U.S., including Memorial Sloan Kettering, University of Pennsylvania, and the Mayo Clinic. This practice-changing trial demonstrates a substantial survival benefit for proton therapy – specifically 10 percent greater for patients receiving proton therapy – paired astoundingly with meaningful reductions in side effects. This win-win combination of therapeutic benefit and reduced side effects is rarely achieved in oncologic studies.

"These groundbreaking survival data in head and neck cancer represent exactly what the proton therapy community has been working toward for more than a decade – rigorous, comparative evidence showing that reducing unnecessary radiation exposure with precise proton therapy can translate into meaningful improvements in patient outcomes," said Jennifer Maggiore, Executive Director of the National Association for Proton Therapy (NAPT). "With the growing body of data now emerging across multiple disease sites, proton therapy is proving to be not just a technological advancement, but a game changer for improving survivorship and quality of life for patients nationwide. Our focus at NAPT is to ensure that every patient who may benefit from this advanced treatment has access to it."

During an NAPT webinar discussing the data, Steven J. Frank, MD, the study's primary investigator and lead author, Professor of Radiation Oncology and Executive Director for Technology and Innovation at The UT MD Anderson Cancer Center, said, "The study results confirm that proton therapy should be the preferred standard of care for oropharyngeal and many other subsites of head and neck cancer."

About Proton Therapy and Phase III Study Published in The Lancet

Proton therapy precisely targets specific cancers to reduce radiation exposure and collateral damage to normal tissue. Traditional radiation therapy uses photons (or X-rays) rather than protons. Photons pass through the body without stopping, leaving both an entry and exit dose of radiation in non-targeted areas which can result in collateral damage to normal tissues.

The multi-institutional study presented is the largest randomized Phase III trial of its kind to date comparing precise proton therapy (IMPT) to traditional photon therapy (IMRT). The study randomized 440 patients at 21 sites across the U.S., including 17 proton centers. Key findings show the following proton therapy benefits over photon therapy:

• 10% improvement in overall survival at 5 years post-treatment
• Substantially reduced feeding tube dependence
• Improved weight maintenance
• Improved acute/subacute swallowing/chewing/quality of life
• Improved work productivity
• Reduced lymphopenia/neutropenia
• High cost-effectiveness compared to IMRT

Isabelle Choi, MD, FACRO, radiation oncologist at Memorial Sloan Kettering, Director of Research at the New York Proton Center, and NAPT's Chair of the Physician Advisory Committee and Board Member, said, "We are entering a pivotal moment in radiation oncology. We are now seeing a consistent pattern: when healthy tissues are spared – such as the heart, lungs, brain, and immune system – patients not only tolerate treatment better, they can have the potential to live longer. Proton therapy has an important role in the future of radiation oncology that allows us to minimize normal tissue side effects, improve quality of life, and even improve disease control outcomes for our patients."

Broadening Evidence-Based Clinical Benefits and Economic Value of Proton Therapy

"This practice-changing trial provides the highest level of clinical evidence that by better protecting normal tissue from unnecessary radiation, proton therapy significantly reduces meaningful toxicities, and it joins a short list of trials which have shown an improvement in overall survival with a change in radiotherapy technique," added Mark W. McDonald, MD, Medical Director at Emory Proton Therapy Center, an NAPT Board Member and an NAPT Physician Advisory Committee member.

In addition to this landmark head and neck cancer trial, several new studies support both the clinical and cost-saving advantages of proton therapy. Together, they provide a compelling case for increased patient access across many tumor sites.

A summary of recent research can be found here.

The Time is Now to Overcome Insurance Barriers

Despite growing evidence, some patients still face coverage restrictions that delay or deny care. Among Medicare beneficiaries in Medicare Advantage plans, more than 90 percent of initial prior authorization denials for proton therapy are overturned on appeal.

"Patients deserve timely access to the treatment their doctors believe will offer them the best chance for recovery," said Maggiore. "NAPT urges payors and legislators to remove outdated or arbitrary barriers so that clinical decisions, not administrative obstacles, determine care."

Patients seeking guidance on insurance or financial issues can access additional NAPT resources here.

Media seeking NAPT materials can access assets here.

About The National Association for Proton Therapy

The National Association for Proton Therapy (NAPT) is an independent nonprofit organization founded in 1990 to educate and increase awareness about the clinical benefits of proton therapy. Its members include 52 of the nation's leading cancer centers, many of which are National Cancer Institute (NCI)-designated comprehensive cancer centers and National Comprehensive Cancer Network (NCCN) members. The mission of NAPT is to work collaboratively to raise public awareness of the clinical benefits of proton therapy, ensure patient choice and access to affordable proton therapy, and encourage cooperative research and innovation to advance the appropriate and cost-effective utilization of proton therapy.

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SOURCE The National Association for Proton Therapy