Proton vs Photon Radiotherapy for Oropharyngeal Cancer
Frank SJ, Busse PM, et al. Proton versus photon radiotherapy for patients with oropharyngeal cancer in the USA: a multicentre, randomised, open-label, non-inferiority phase 3 trial. Lancet 2025.
The Clinical Question
IMRT with concurrent chemotherapy is standard for oropharyngeal cancer, but toxicity is substantial — over 60% of patients become feeding tube dependent.
Proton therapy reduces radiation to normal tissues. Does this translate into clinical benefit?
This is the first phase 3 trial comparing proton vs photon radiotherapy for head and neck cancer.
Study Design
Multicenter, randomized, non-inferiority phase 3 trialat 21 US centers. 440 patients with stage III/IV oropharyngeal cancer (95% HPV-positive) randomized to IMPT vs IMRT, both with concurrent chemotherapy.
Primary endpoint: Progression-free survival (non-inferiority margin: 9 percentage points)
Key Results
Progression-Free Survival
| Outcome | IMPT | IMRT |
|---|---|---|
| 5-year PFS | 81.3% | 76.2% |
| HR (95% CI) | 0.88 (0.57–1.35) | — |
| p (non-inferiority) | 0.005 | — |
Non-inferiority achieved.
Survival Benefit
| Outcome | IMPT | IMRT |
|---|---|---|
| 5-year OS | 90.9% | 81.0% |
| HR (95% CI) | 0.58 (0.34–0.99) | — |
| p-value | 0.045 | — |
42% reduction in death risk with protons.
Toxicity
| Grade 3+ | IMRT | IMPT |
|---|---|---|
| Lymphopenia | 89% | 76% |
| Dysphagia | 49% | 34% |
| G-tube at 60 days | 40% | 27% |
33% reduction in feeding tube dependence.
Limitations
- 23% crossover (insurance issues)
- Limited to academic proton centers
- 93% White population
Bottom Line
IMPT is now a standard-of-care option for oropharyngeal cancer — non-inferior disease control, 42% reduction in death risk, significantly reduced toxicity.
Access remains limited and insurance coverage inconsistent. For patients who can access protons, this is Level 1 evidence.
Full Paper: https://doi.org/10.1016/S0140-6736(25)01962-2
Found this useful? Forward to a colleague who treats head and neck cancer.
Until next week, Krishnakumar Thankappan
Head & Neck Oncology Journal Club