The Impact of Tonsillectomy upon the Risk of Oropharyngeal Carcinoma Diagnosis and Prognosis in the Danish Cancer Registry.

The incidence of oropharyngeal carcinoma, involving palatine and lingual tonsils, is increasing globally. This significant rise is driven by human papillomavirus. Whether palatine tonsillectomy affects risk of diagnosis with oropharyngeal carcinoma is unknown. The association between tonsillectomy and incidence of oropharyngeal carcinoma was explored in the Danish Cancer Registry. The association between tonsillectomy and oropharyngeal carcinoma was analyzed by time since first registration of tonsillectomy. Tonsillectomy was a time-dependent variable. Individuals were censored for death, emigration, or tonsillectomy within incident year of diagnosis. Incidence rate ratios (RR) were estimated by Poisson regression models and adjusted for confounders. Kaplan-Meier survival analyses were compared by the log-rank test, and HRs were estimated by Cox proportional hazards models. From 1977 to 2012, the incidence of tonsillectomies significantly decreased, whereas the incidence of oropharyngeal carcinoma significantly increased. Tonsillectomy was not associated with risk of oropharyngeal carcinoma or malignancies of other anatomic sites, including base of tongue. However, tonsillectomy significantly reduced risk of diagnosis with tonsil carcinoma [RR, 0.40; 95% confidence interval (CI), 0.22-0.70]. The risk of diagnosis with tonsil carcinoma at age <60 years was significantly decreased (RRadj, 0.15; 95% CI, 0.06-0.41) after tonsillectomy. Tonsillectomy within 1 year of diagnosis with tonsil carcinoma was associated with significantly improved overall survival (HR, 0.53; 95% CI, 0.38-0.74). In conclusion, remote history of tonsillectomy reduces the risk of diagnosis with tonsil carcinoma. These data inform risk and benefit of tonsillectomy, a common procedure and design of secondary prevention trials. ©2015 American Association for Cancer Research.