Clinical and Prognostic Significance of the Eighth Edition Oral Cancer Staging System

Objectives: The most notable changes in the eighth edition of the AJCC Cancer Staging System include incorporating the depth of invasion (DOI) into T staging and extranodal extension (ENE) into N staging. In this study, we retrospectively assessed the prognostic and clinical implications of the eighth TNM staging system. Materials and Methods: Patients with Oral Squamous Cell Carcinoma (OSCC) who were treated surgically between 2010 and 2017 were retrospectively reviewed. Tumors were first staged according to the seventh edition and restaged using the eighth edition. The prognostic value of the resultant upstaging was evaluated. Results: Integrating the DOI into the T classification resulted in the upstaging of 65 patients, whereas incorporating ENE into the N staging resulted in the upstaging of 18 patients (p < 0.001). Upstaging due to DOI integration had no significant effect on OS or DSS (p > 0.05). Conclusion: Our results demonstrate the importance of incorporating ENE into nodal staging and considering adjuvant therapy when ENE is present.