Intensity‐modulated radiotherapy with planned Gamma Knife radiosurgery boost for head and neck cancer with extensive disease in proximity to critical structures

BACKGROUND: To describe intensity‐modulated radiotherapy (IMRT) with Gamma Knife Radiosurgery (GKRS) boost for locally advanced head and neck cancer (HNC) with disease near dose‐limiting structures. METHODS: Patients with HNC treated with IMRT/GKRS as part of a combined modality approach between 2011 and 2021 were reviewed. Local control, overall survival and disease‐specific survival were estimated using the Kaplan Meier method. RESULTS: Twenty patients were included. Nineteen patients had T3‐4 tumors. Median follow‐up was 26.3 months. GKRS site control was 95%. Two patients progressed at the treated primary site, one patient failed at the edge of the GKRS treatment volume, with no perineural or intracranial failure. 2‐year OS was 94.7% (95% CI: 85.2%–100%). Concurrent chemotherapy was given in nine patients (45%). One patient (5%) received induction/concurrent chemotherapy. Brain radionecrosis occurred in three patients, one of which was biopsy‐proven. CONCLUSIONS: IMRT plus GKRS boost results in excellent disease control near critical structures with minimal toxicity.