Stereotactic body radiotherapy for recurrent squamous cell carcinoma of the head and neck: results of a phase I dose-escalation trial.

PURPOSE: To evaluate the safety and efficacy of stereotactic body radiotherapy (SBRT) in previously irradiated patients with squamous cell carcinoma of the head and neck (SCCHN).

PATIENTS AND METHODS: In this Phase I dose-escalation clinical trial, 25 patients were treated in five dose tiers up to 44 Gy, administered in 5 fractions over a 2-week course. Response was assessed according to the Response Evaluation Criteria in Solid Tumors and [(18)F]-fluorodeoxyglucose standardized uptake value change on positron emission tomography-computed tomography (PET-CT).

RESULTS: No Grade 3/4 or dose-limiting toxicities occurred. Four patients had Grade 1/2 acute toxicities. Four objective responses were observed, for a response rate of 17% (95% confidence interval 2%-33%). The maximum duration of response was 4 months. Twelve patients had stable disease. Median time to disease progression was 4 months, and median overall survival was 6 months. Self-reported quality of life was not significantly affected by treatment. Fluorodeoxyglucose PET was a more sensitive early-measure response to treatment than CT volume changes.

CONCLUSION: Reirradiation up to 44 Gy using SBRT is well tolerated in the acute setting and warrants further evaluation in combination with conventional and targeted therapies.