The 8 th UICC/AJCC TNM edition for non-small cell lung cancer staging: getting off to a flying start?

Non-small cell lung cancer (NSCLC) represents the primary cause of cancer death in both men and women (1). Proper disease staging at diagnosis is crucial in providing an accurate prognosis and guiding towards the most appropriate treatment strategy. The Union for International Cancer Control (UICC)/American Joint Committee on Cancer (AJCC) TNM classification has evolved through the years and is the golden standard for solid tumor staging. In comparison with the 7th edition of the staging system for NSCLC, significant revisions have been proposed for the 8th edition (2). At this regard, the International Association for the Study of Lung Cancer (IASLC) Staging and Prognostic Factors Committee collected an enormous database of 94,708 cases and compared the performance of the two versions (3). One of the major drawbacks was the geographically inhomogeneous distribution: Asia provided for nearly 80% of tumors (while it was almost 50% in the previous database). Moreover, most of the data for the N descriptor were obtained from Japan, representing a nodal categorization based upon the Japanese Naruke map (4); a further validation was therefore advisable according to Mountain-Dressler modification of the American Thoracic Society map, considering the small quote of data representing western countries patients’ cohort; another critical issue was the tiny percentage of non-surgical patients (only 563 cases)