Safety and efficacy of hypofractionated stereotactic body reirradiation in head and neck cancer: Long-term follow-up of a large series.

BACKGROUND The purpose of this study was to report long-term outcomes for a large cohort of patients with head and neck squamous cell carcinoma (HNSCC) who underwent stereotactic body radiotherapy (SBRT) reirradiation. METHODS From 2002 to 2011, 85 patients with previously irradiated HNSCC were treated with SBRT to 94 lesions. Some underwent surgery (29%), and many were treated with induction, concurrent, and/or adjuvant chemotherapy or biologic therapy (70%). RESULTS Reirradiation occurred at a median interval from initial radiotherapy (RT) of 32 months. Median follow-up for survivors was 17.3 months. Two-year Kaplan-Meier estimates of overall survival (OS) and locoregional control for patients and lesions treated with curative intent were 24% and 28%, respectively. Interval from initial RT to SBRT of 2 years or more was associated with improved OS (p = .019). Five patients had grade 3 or higher late toxicity (5.9%). CONCLUSION SBRT reirradiation results in limited toxicity. Further research is needed to refine optimal roles for SBRT and intensity-modulated radiotherapy (IMRT) reirradiation.