Prognostic performance of the American Joint Committee on Cancer 8th edition of the TNM staging system in patients with early oral tongue cancer

Background The 8th edition of the American Joint Committee on Cancer's (AJCC) staging system for oral cavity cancer incorporates pathological features. We aimed to assess whether these changes results in better risk stratification of patients with early oral tongue squamous cell carcinoma (OTSCC). Methods Overall survival (OS) and disease-specific survival (DSS) of 244 patients were calculated using the Kaplan-Meier method. Multivariate analysis with stepwise selection was performed using Cox proportional hazards regression. Results Sixty-two patients (25%) were upstaged using the 8th edition. Multivariate analysis revealed that overall stage using the 8th edition of the AJCC staging system but not using the 7th edition was a significant predictor for both OS and DSS. The 8th edition had lower Akaike information criterion and improved concordance index values compared with the 7th edition. Conclusion The 8th edition of AJCC allows better risk stratification and more precise counseling of patients with OTSCC who were previously considered at low risk.