Ipsilateral neck radiotherapy in N2b well‐lateralized tonsil cancer – Approach with caution

BACKGROUND: Treatment of the uninvolved neck in well-lateralized tonsillar squamous cell carcinoma is controversial. We became concerned after a number of contralateral neck recurrences (CNRs) in patients receiving ipsilateral radiotherapy (RT). METHODS: This is a single center retrospective series including patients with well-lateralized tonsillar cancer treated with ipsilateral neck RT between 2004 and 2011. RESULTS: We identified 53 patients treated with ipsilateral neck RT during the study period. The rate of CNR was 7.5% (4 of 53). All four patients had p16-positive, T1, N2b, M0 tumors. The subgroup of patients with N2b disease (28 of 53) had a CNR of 14.3%. We subsequently switched to treat patients with N2b with bilateral neck RT. We analyzed the outcomes of 23 patients with N2b treated with bilateral neck intensity-modulated RT (IMRT) and observed no CNRs. CONCLUSIONS: We observed a higher than expected rate of CNR in the N2b population. Bilateral neck IMRT for these patients represents a safe alternative.