Prognostic Significance of Smoking in Human Papillomavirus–Positive Oropharyngeal Cancer Under American Joint Committee on Cancer Eighth Edition Stage

Objective: To determine the prognostic significance of smoking in human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPSCC) when considering American Joint Committee on Cancer eighth edition (AJCC-8) stage. Study Design: Retrospective cohort study. Methods: Three hundred seventeen HPV-positive OPSCC patients with known AJCC-8 stage and smoking status (<10 or ≥10 pack-years) seen at a tertiary center from 1997 to 2017 were studied. We used the Kaplan-Meier method to compare 5-year overall survival (OS) by smoking status and by clinical AJCC-8 stage and smoking status combined. Hazard ratios (HRs) were estimated with Cox proportional hazard regression for the independent effects of smoking and AJCC-8 stage. We also studied pathologic stage and estimated the combined effects of smoking and clinical stage. Results: The ≥10 pack-years smokers had worse 5-year OS than <10 pack-years smokers (93.6%; 95% confidence interval (CI): 89.7-97.8 vs. 82.3%; 95% CI: 76.0%-89.1%). When stratified by AJCC-8 clinical stage, only stage I <10 pack-years smokers (98.7%; 95% CI: 96.3%-100.0%) had significantly better 5-year OS than their ≥10 pack-years (84.8%; 95% CI: 76.4%-94.1%) counterparts. In a multivariable analysis, ≥10 pack-years smoking was associated with increased hazard of death when adjusting for AJCC-8 clinical (HR: 2.52; 95% CI: 1.16-5.46) and pathologic (HR: 5.21; 95% CI: 1.47-18.5) stage. In both analyses, stage III patients demonstrated worse survival than stage I, and smoking had greater impact at lower stages. Conclusions: Smoking is a negative prognosticator in HPV-positive OPSCC and interacts with AJCC-8 clinical stage. It is important to understand the impact of smoking in HPV-positive disease when considering treatment plans and deintensification trials. Level of Evidence: 2b Laryngoscope, 130: 1961–1966, 2020.