The phase III TORPEdO trial reported no meaningful differences between intensity-modulated radiation therapy (IMRT) and proton beam therapy at 1 year in terms of patient-reported quality of life, swallowing function, or feeding tube dependence for individuals with locally advanced oropharyngeal cancer. These results were presented by David Thomson, MD, of The Christie NHS Foundation Trust in Manchester, UK, at the 2025 American Society for Radiation Oncology (ASTRO) Annual Meeting.1
“We found no evidence of a late patient-reported physical side effects or quality of life between proton beam therapy and IMRT, with contemporary IMRT performing better than we anticipated,” stated Dr. Thomson. “Our results confirm that high-quality IMRT is a very good treatment for this disease.”
Study Details and Results
In the TORPEdO trial, 205 patients with locally advanced oropharyngeal squamous cell carcinoma were randomly assigned 2:1 to receive either intensity-modulated proton therapy (n = 136) or IMRT (n = 69) with concurrent cisplatin chemotherapy at centers across the UK between 2020 and 2023. The median patient age was 57 years; almost 80% of patients were male, and nearly 70% had fewer than 10 pack-years of smoking history.
The trial’s co-primary endpoints combined clinical measures and patient-reported outcomes. Clinicians assessed feeding tube use and severe weight loss (20% from baseline), and patients were asked to self-report side effects and quality of life via questionnaires at baseline and multiple timepoints after treatment.
We found no evidence of a difference in late patient-reported physical side effects or quality of life between proton beam therapy and IMRT, with contemporary IMRT performing better than we anticipated.— DAVID THOMSON, MD
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At 1-year posttreatment, dependence on a feeding tube was very low in both groups (1.7% each). Severe weight loss occurred more frequently in the group receiving proton beam therapy (18.2%) vs those who received IMRT (5.7%). The trial’s design specified that the clinical endpoint would be a composite of these measures, and no statistically significant difference was observed between the treatment arms.
These findings offer additional context alongside a phase III trial reported in 2024, which also compared these therapies in locally advanced oropharyngeal squamous cell carcinoma.2 The earlier study found proton therapy reduced feeding tube dependence at the conclusion of treatment when compared with IMRT.
In the TORPEdO trial, for patient-reported outcomes, no differences were observed between the proton and IMRT arms 1 year after treatment on a composite functional index for saliva, taste, chewing, swallowing, speech, and appearance (University of Washington Quality-of-Life questionnaire [0 = worst score; 100 = best score]3: 78.3 for protons vs 77.1 for IMRT) nor on a measure specifically for swallowing function (MD Anderson Dysphagia Inventory4: 79.5 vs 79.7, respectively).
Survival rates were similarly high for both groups. At a
median follow-up of 28.3 months, the 2-year freedom from cancer returning at or near the original tumor site was 94.3% for proton therapy and 96.8% for IMRT, with overall survival rates of 94.6% for proton therapy and 95.3% for IMRT.
“IMRT performed better than expected based on historical data involving patient-reported outcomes, and long-term feeding tube dependence was much lower than reported in previous trials,” said Dr. Thomson. “It’s an encouraging finding that patients with this type of cancer can receive excellent care at their local treatment centers with this advanced technology.”
In addition to focusing on patient-reported, clinically relevant outcomes, Dr. Thomson said a strength of the TORPEdO trial was its rigorous quality assurance. Treatment planning and delivery in both arms met strict standards overseen by the UK’s National Radiotherapy Trials Quality Assurance Group. “We wanted to be confident that both arms delivered the highest-quality care to ensure a valid comparison between these advanced techniques.”
Photon (IMRT) vs Proton Therapy
IMRT, an advanced photon-based technique, shapes and modulates radiation beams to precisely target tumors. Photon beams effectively eliminate cancer tumors but scatter bits of radiation along the way, which can lead to side effects in the area treated. Proton therapy, a newer approach, uses proton beams that deposit less radiation along their path to the tumor, potentially sparing surrounding healthy tissue and resulting in possibly fewer side effects. Proton therapy requires specialized facilities and training, however, and is less widely available and substantially more expensive than photon beam therapy, or IMRT, noted the investigators.
“There’s been interest in the use of proton beam therapy specifically for head and neck cancers because of the intricate nature of treating this area, with nearby organs for chewing, swallowing, speech, hearing, and other important functions. Trying to reduce the radiation dose to these organs is important, because it may result in fewer side effects and improved functioning,” Dr. Thomson said.
DISCLOSURE: The TORPEdO trial was funded by Cancer Research UK, with additional support from The Taylor Family Foundation. The trial was sponsored by The Institute of Cancer Research, centrally managed by The Institute of Cancer Research Clinical Trials and Statistics Unit, and supported by the National Institute for Health Research–funded National Radiotherapy Trials Quality Assurance Group. Dr. Thomson reported no conflicts of interest. For full disclosures of all study authors, visit amportal.astro.org.
REFERENCES
1. Thomson D, Price J, Tyler M, et al: Primary results for the phase III trial of toxicity reduction using proton beam therapy for oropharyngeal cancer (TORPEdO; CRUK/18/010). 2025 ASTRO Annual Meeting. Abstract LBA 02. Presented September 29, 2025.
2. Frank SJ, Busse P, Rosenthal DI, et al: Phase III randomized trial of intensity-modulated proton therapy versus intensity-modulated photon therapy for the treatment of head and neck oropharyngeal carcinoma. 2024 ASCO Annual Meeting. Abstract 6006. Presented June 4, 2024.
3. The University of Washington Head and Neck Cancer Quality of Life Questionnaire (HaNDLE-on-QoL). Available at http://www.handle-on-qol.com/Index.aspx. Accessed October 22, 2025.
4. Chen AY, Frankowski R, Bishop-Leone J, et al: The development and validation of a dysphagia-specific quality-of-life questionnaire for patients with head and neck cancer: The MD Anderson dysphagia inventory. Arch Otolaryngol Head Neck Surg 127:870-876, 2001.
