Prognostic value of p16 expression and alcohol consumption in Japanese patients with oropharyngeal squamous cell carcinoma

BACKGROUND The prevalence and prognostic value of human papillomavirus-related oropharyngeal squamous cell carcinoma (OPSCC) in Japan has not been evaluated. METHODS Over a 12-year period, the authors used immunohistochemistry to evaluate the expression of p16 (a cyclin-dependent kinase inhibitor and tumor suppressor) in samples from 173 patients with OPSCC at a single institution and to determine its prevalence and influence on disease prognosis. RESULTS The prevalence of p16-positive OPSCC was 33.7% in tonsillar carcinoma, 28.6% in tongue base carcinoma, 0% in posterior wall carcinoma, and 18.8% in soft palate carcinoma. The prevalence of p16-positive OPSCC tumors increased from 15.2% during 2000 to 2003 up to 33.3% during 2008 to 2011; during the same periods, among nonsmokers, the prevalence of p16-positive OPSCC tumors increased from 21.2% to 27.8%; and, among nondrinkers, prevalence increased from 6.1% to 25%. Multivariate analysis identified p16 expression and alcohol consumption as significant, independent prognostic markers of OPSCC. CONCLUSIONS The current results suggest that the incidence of human papillomavirus-related OPSCC in Japan is increasing and indicate that p16 expression and alcohol consumption may be significant prognostic markers of survival for patients with OPSCC in Japan. Cancer 2013;119:20052011. (c) 2013 American Cancer Society.