Adenoid cystic carcinoma of the head and neck: Patterns of recurrence and implications for intensity‐modulated radiotherapy

Background We seek to inform radiotherapy (RT) delivery for adenoid cystic carcinoma of the head and neck (ACC) by evaluating RT techniques and recurrence patterns. Methods We identified patients with ACC treated with curative‐intent RT from 2005 to 2021. Imaging was reviewed to determine local recurrence (LR). Results Ninety‐one patients were included. The 5‐year LR risk was 12.2% (6.6–22.7). One patient each experienced a marginal and out‐of‐field recurrence. Patients receiving >60 Gy postoperatively had a 5‐year LR risk of 0% compared to 10.7% (4.2–27.2) with ≤60 Gy. Those receiving 70 and 60 and 70 Gy may improve control in the postoperative and definitive settings, respectively. Elective nodal treatment can be omitted in well‐selected patients.