Subsite variation in survival of oropharyngeal squamous cell carcinomas 2004 to 2011.

Objectives/hypothesis: To evaluate subsite-specific differences in survival between squamous cell carcinomas of the base of tongue and tonsillar fossa in a modern cohort likely to have been treated with intensity-modulated radiation therapy, chemotherapy for stage III and IV, and have had a high incidence of human papillomavirus-associated tumors.

Study Design: Retrospective cohort analysis utilizing data from the Surveillance, Epidemiology, and End Results program of patients with base of tongue and tonsillar fossa squamous cell carcinoma from 2004 to 2011.

Methods: The cohort included 15,299 primary base of tongue and tonsillar fossa squamous cell carcinoma patients without distant metastases treated between 2004 and 2011. Subsite differences in overall survival and disease-specific survival were examined with Kaplan-Meier curves. Multivariate cox proportional hazard ratios were estimated for overall and disease-specific survival.

Results: The cohort included 7,220 (47.2%) base of tongue and 8,079 (52.8%) tonsillar fossa squamous cell carcinoma patients. Overall survival with all stages combined favored tonsillar fossa (P < .001) and remained superior when stratified by stage. In multivariate analyses adjusted for age, gender, race, and treatment, the hazard ratio for overall survival was superior for tonsillar fossa tumors compared to base of tongue tumors for all stages (stage 1, P = .041; stage 2, P = .006; stages 3 and 4, P < .001). Disease-specific survival also favored improved outcomes for tonsillar fossa.

Conclusions: In this large modern cohort, overall and disease-specific survival favored outcomes in tonsillar fossa compared with base of tongue. Further study is required to evaluate factors that influence survival differences between tonsillar fossa and base of tongue despite modern therapy.

Level Of Evidence: 4 Laryngoscope, 127:1087-1092, 2017.