A phase I/II study evaluating the feasibility and safety of delivering adjuvant hypofractionated radiotherapy in resected oral cavity cancers (HYPO-ART study)

To evaluate the tolerability and efficacy of adjuvant Hypofractionated radiotherapy in resected oral cavity cancer patients. Post-operative oral cavity cancer patients with indications for adjuvant (chemo) radiotherapy were enrolled. T3/T4 disease, positive lymph nodes(s), lympho-vascular invasion, and/ or perineural invasion were considered intermediate risk factors for which a radiation dose of 50Gy over four weeks was delivered. Extra-nodal extension and/or positive margins were considered high-risk factors for which a radiation dose of 62.5Gy over five weeks was delivered. The primary end-point was the incidence of acute radiation-induced toxicities. Secondary endpoints were locoregional control and overall survival. 38 patients were enrolled in the trial and completed planned radiotherapy treatment. No grade 4 toxicity was observed. Acute grade 3 toxicity included oral mucositis in 60.5% of patients and dysphagia in 18.3% of patients. 71% of patients required nasogastric tube placement and 50% needed day-care support. At a median follow-up of 20.35 months, 57.9% were alive with no evidence of disease, and 31.6% of patients had a loco-regional recurrence. Loco-regional control and overall survival at one year were 68% and 84%; at two years, they were 59% and 59%, respectively. Moderately hypofractionated radiotherapy is well tolerated and can safely be delivered for resected oral cavity tumors with optimal supportive care while maintaining similar oncological outcomes compared to conventional fractionation.