A review of head and neck cancer staging system in the TNM classification of malignant tumors (eighth edition).

A number of major modifications were made to the classification of head and neck carcinomas in the eighth edition of the American Joint Committee on Cancer, Cancer Staging Manual and Union for International Cancer Control TNM classification of Malignant Tumors. These modifications were aimed at improving the prognosis prediction accuracy of the system. In this article, we review the new edition of the TNM classification system. Among the several changes in the new system, a separate algorithm for p16-positive oropharyngeal carcinoma was included, as were new chapters on 'Head and Neck Skin Carcinoma' and 'Unknown Primary Carcinoma-Cervical Nodes.' Changes to Tumor (T) classification were made by introducing the depth of invasion of oral carcinoma, whereas changes to Node (N) classification were made by adding extra-nodal extension. It is believed that these changes will help improve the accuracy of the system in the prediction of prognosis. However, it is necessary to verify their validity through further clinical research.