Recent advances in refinement of the NPC TNM staging system

Abstract The American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) TNM (tumor node metastasis) classification for Nasopharyngeal carcinoma (NPC) is a valuable stool for evaluating tumor progression, guiding clinical treatment strategies as well as predicting prognosis. The 8th edition TNM classification (TNM-8) has notable limitations, such as overlapping prognosis between T2 and T3 categories as well as unbalanced distribution in the T and N classification and so on. The 9th edition TNM classification (TNM-9) was published in January this year and offered significant improvements over its predecessor, which provides more precise prognosis prediction and more appropriate clinical treatment guidance. A set of revisions were made in the TNM-9, containing upstaging N1-2 with advanced image-identified extranodal extension to N3 classification, subdividing M classification into M1a (≤ 3 metastatic lesions) and M1b (> 3 metastatic lesions), and adjusting stage grouping. This commentary summarizes and evaluates the revisions in the TNM-9, and explores future research directions for further refinement of the staging system.