[Diagnostic. The new TNM classification for lung cancer]

The last edition of the TNM-based staging classification of lung cancer is based on the Mountain proposal published in 1997. However, due to the multiple methodological problems in the series and in the analysis, an international multidisciplinary panel of experts performed under the auspices of the International Association for the Study of Lung Cancer (IASLC) a huge retrospective study, called the IASLC international staging project. The objective was to propose to the UICC and to the AJCC changes to the TNM system and to the stages grouping, based on an adequate methodological approach with internal and external validations. For T, size of the tumour has been taken into account as well as satellite nodules. For N, no change has been performed but a more practical definition of nodal zones has been proposed for further investigations. For M, pleural and pericardial invasions have moved from T4 to M1. Those changes have been incorporated in the new system with a new grouping in stages.