Randomized phase 2 trial: proton therapy cut acute mucositis versus IMRT in unilateral postoperative head and neck cancer, with equal 3-year control

In a multicentre randomized phase 2 trial, 98 patients (54 proton, 44 IMRT) receiving postoperative unilateral radiotherapy for well-lateralized head and neck cancer were given 60 Gy in 30 fractions. Acute grade 2 or higher oral mucositis, the primary endpoint, occurred in 7.4% with protons versus 22.7% with IMRT (P=0.03), and grade 2 or higher dysgeusia in 9.3% versus 31.8% (P=0.005). Rates of grade 3 or higher dermatitis and grade 2 or higher dysphagia were comparable, no late grade 3 toxicity occurred in either arm, and three-year local control, progression-free and overall survival were high and similar. The benefit demonstrated here is reduced acute mucosal toxicity, not better cancer control; this is a phase 2 result and does not by itself establish protons as the standard in this setting.