Tumor stage, human papillomavirus and smoking status affect the survival of patients with oropharyngeal cancer : An Italian validation study

Background: Tumor human papillomavirus (HPV) status strongly affects overall survival (OS) of oropharyngeal cancer (OPC) patients. Recently, three groups with different outcomes were identified based on HPV status, smoking history and tumor stage. Our objective was to validate this model using a single-institutional retrospective database. Patients and methods: Patients (n = 120) diagnosed with OPC at our institution, treated with concomitant cisplatin plus radiotherapy (RT) (n = 64), induction chemotherapy followed by concomitant chemoradiation (n = 39) or RT alone (n = 17), were stratified in three groups with respect to the risk of death (low 26, intermediate 46 and high 49 patients) according to tumor p16 expression as surrogate of HPV status, pack-years of tobacco smoking and nodal/tumor stage. Group-stratified Kaplan-Meier OS curves were estimated and compared using the log-rank test. Results: The 2-year OS estimates were 100%, 86% and 70%, respectively. The difference between the survival curves was statistically significant (P = 0.009). The Harrell's concordance index was 0.70. The calibration plot showed a good concordance between our results and those observed in the original study. Conclusions: This study validates the risk grouping previously identified. Risk-driven clinical decision making and trial designs will help in better defining the most appropriate treatment in OPC patients.