Human papilloma virus and survival of oropharyngeal cancer patients treated with surgery and adjuvant radiotherapy.

Impact of p16 protein, a surrogate marker for human papilloma virus induced cancer, p53 and EGFR as well as clinical factors on survival in a patient cohort with oropharyngeal squamous cell carcinoma (OPSCC) treated by surgical resection and adjuvant radiotherapy (RT) +/- concomitant chemotherapy (CT). This is a retrospective analysis of patient's charts and tumor tissue. 57 patients were consecutively included and their tumor tissue assembled on a tissue microarray following immunohistochemical analysis. Survival times were estimated by means of Kaplan-Meier analysis. The importance of clinical and immunohistochemical factors for outcome was estimated by cox proportional hazard models. With 88% 5-year overall survival, 91% 5-year disease-specific survival and 91% 5-year disease-free survival, respectively, we found excellent survival rates in this surgically treated patient cohort of mainly advanced OPSCC (93% AJCC stage III or IV). The only factors positively influencing survival were p16 overexpression as well as p53 negativity and even more pronounced the combination of those biomarkers. Survival analysis of patients classified into three risk categories according to an algorithm based on p16, smoking, T- and N-category revealed a low, intermediate and high-risk group with significant survival differences between the low and the high-risk group. Patients with OPSCC can be successfully treated by surgery and adjuvant RT +/- CT with a clear survival benefit of p16 positive, p53 negative patients. We recommend considering a combination of immunohistochemical (p16, p53) and clinical factors (smoking, T- and N-category) for risk stratification.