Radiotherapy alone or combined with chemotherapy as definitive treatment for squamous cell carcinoma of the tonsil

This study is aimed at updating our institution's experience with definitive radiotherapy (RT) for squamous cell carcinoma of the tonsil. We reviewed 531 patients treated between 1983 and 2012 with definitive RT for squamous cell carcinoma of the tonsil. Of these, 179 patients were treated with either induction (n = 19) or concomitant (n = 160) chemotherapy. Planned neck dissection was performed on 217 patients: unilaterally in 199 and bilaterally in 18 patients. Median follow-up was 5.2 years for all patients (range 0.1–31.6 years) and 8.2 years for living patients (range 1.9–31.6 years). The 5-year local control rates by T stage were as follows: T1, 94 %; T2, 87 %; T3 79 %; T4, 70 %; and overall, 83 %. Multivariate analysis revealed that local control was significantly influenced by T stage and neck dissection. The 5-year cause-specific survival rates by overall stage were as follows: I, 94 %; II, 88 %; III, 87 %; IVA, 75 %; IVB, 52 %; and overall, 78 %. Multivariate analysis revealed that cause-specific survival was significantly influenced by T stage, N stage, overall stage, fractionation, neck dissection, sex, and ethnicity. Of 77 patients treated with ipsilateral fields only, contralateral neck failure occurred in 1 %. The rate of severe complications was 12 %. Definitive RT for patients with tonsillar squamous cell carcinoma provides control rates equivalent to other modalities with a comparatively low incidence of late complications. Patients with anterior tonsillar pillar or tonsillar fossa primaries that are well lateralized with no base of tongue or soft palate extension may be treated with ipsilateral fields.