Impact of American Joint Committee on Cancer Eighth Edition clinical stage and smoking history on oncologic outcomes in human papillomavirus-associated oropharyngeal squamous cell carcinoma

Background The purpose of this study was to evaluate the AJCC eighth edition clinical staging system for human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma and to further understand how clinical stage and smoking history affect oncologic outcomes. The purpose of this study was to present the understanding of how clinical stage and smoking history affect oncologic outcomes in human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (SCC) is critical for selecting patients for treatment deintensification. Methods Kaplan-Meier and Cox regression were used to evaluate overall survival (OS), locoregional recurrence-free survival (LRFS), and distant recurrence-free survival (DRFS). Concordance statistics (C-indices) were used to compare discriminating ability. Results The OS and DRFS but not LRFS were significantly distributed using the American Joint Committee on Cancer (AJCC) seventh and eighth editions criteria. The C-indices for OS, LRFS, and DRFS were 0.57, 0.54, and 0.60, respectively, using the AJCC seventh edition, and 0.63, 0.53, and 0.65, respectively, using the AJCC eighth edition. On multivariate analysis, 1 + pack-year smoking history correlated with OS (hazard ratio [HR] 1.96; 95% confidence interval [CI] 1.2-3.1; P < .01) but not LRFS or DRFS. Conclusion These results support implementation of the AJCC eighth edition for HPV-associated oropharyngeal SCC. Clinical stage may be more important than smoking history in selection for deintensification.