Clinical TNM staging of thymic epithelial malignancies

The International Thymic Malignancy Interest Group (ITMIG) and the International Association for the Study of Lung Cancer (IASLC) formed the Thymic Domain of the Staging and Prognostic Factors Committee (TD-SPFC) to develop the first stage classification system for thymic epithelial tumors (TETs) which was published in the TNM Classification of Malignant Tumours issued by the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC), now in 8th edition. This system was developed from evidence-based analysis of the large ITMIG database of TETs, in conjunction with expert opinion. Until its publication in December 2017, there had been no universally accepted, standard means of classifying these tumors, although Masaoka-Koga staging system had most closely approached this standard. This brief article will summarize this new stage classification system for TETs, highlighting its differences with Masaoka-Koga and relevant next goals.