INTRODUCTION: The aim of this study is to analyze all metastatic (M) categories of the current @entity5 , node, and @entity3 (TNM) classification of @entity2 with the objective of providing suggestions for modifications of the M component in the next edition of the TNM classification for @entity2 . METHODS: The new International Association for the Study of @entity2 database was created from 94,708 @entity1 diagnosed as having @entity2 between 1999 and 2010. Including further @entity1 submitted through the electronic data capture system to @entity5 Research and Biostatistics until 2012, all together 1059 @entity1149 cases were available for a detailed analysis of the clinical M categories. Overall survival was calculated using the Kaplan-Meier method, and prognosis was assessed using a Cox proportional hazards regression analysis. RESULTS: No significant differences were found among the M1a ( @entity3 within the chest cavity) descriptors. However, when M1b (distant @entity3 outside the chest cavity) were assessed according to the number of @entity3 , @entity5 with a single @entity3 in a single organ had significantly better prognosis than those with multiple @entity3 in one or several organs. CONCLUSIONS: In this revision of the TNM classification, cases with @entity1143 , contralateral/bilateral lung nodules, contralateral/bilateral pleural nodules, or a combination of multiple of these parameters should continue to be grouped as M1a category. Single metastatic lesions in a single distant organ should be newly designated to the M1b category. @entity75 in a single organ or multiple lesions in multiple organs should be reclassified as M1c category. This new division can serve as a first step into providing rational definitions for an oligometastatic disease stage in @entity1149 in the future.

The IASLC @entity2 Staging Project: Proposals for the Revision of the M Descriptors in the Forthcoming Eighth Edition of the TNM Classification of XXXX .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity1143 :: ('MESH:D010996', 'Disease') :: ['pleural/pericardial effusions'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'Cancer', 'tumors'] @entity75 :: ('MESH:D001927', 'Disease') :: ['Multiple lesions'] @entity2 :: ('MESH:D008175', 'Disease') :: ['Lung Cancer lung cancer', 'lung cancer'] @entity1149 :: ('MESH:D002289', 'Disease') :: ['non-small-cell lung cancer'] @entity3 :: ('MESH:D009362', 'Disease') :: ['metastasis', 'metastases']
@entity2 :: (MESH:D008175,Disease) :: ['Lung Cancer']
