Multiple cervical lymph node involvement and extra-capsular extension predict for contralateral nodal recurrence after ipsilateral radiotherapy for squamous cell carcinoma of the tonsil.

BACKGROUND: Ipsilateral radiotherapy is an established technique for treating well-lateralised tonsillar tumours. Concerns exist regarding the risk of contralateral nodal failure, particularly in patients with ipsilateral nodal involvement at presentation. In this study, we retrospectively reviewed the clinical outcomes of patients treated with ipsilateral radiotherapy aiming to identify factors that predispose to a higher risk of contralateral nodal recurrence. METHODS: Retrospective case note review of all patients with tonsillar cancer who were treated using ipsilateral radiotherapy between September 1995 and September 2011 was performed. Demographics, T and N stage, involvement of soft palate and/or tongue base, presence of extra-capsular spread (ECS) and treatment details were recorded. Kaplan-Meier curves for treatment outcomes were generated. RESULTS: A total of 136 patients were identified. Median follow-up was 4.2years. Twelve (9%) patients had loco-regional recurrence. Eight patients (6%) had contralateral recurrence. N2b disease, ECS and number of pack-years of smoking were associated with contralateral nodal recurrence. Five-year overall survival was 89%, loco-regional disease-free survival 90%, disease-free survival 86% and distal recurrence-free survival 96%. CONCLUSION: N2b disease, ECS and a greater than 10 pack-year smoking history are risk factors for contralateral nodal recurrence in well-lateralised tonsillar cancers. Prophylactic irradiation of the contralateral neck should be recommended in this group of patients.