Elsevier

Journal of Thoracic Oncology

Volume 10, Issue 11, November 2015, Pages 1515-1522
Journal of Thoracic Oncology

State of the Art: Concise Review
The IASLC Lung Cancer Staging Project: Proposals for the Revision of the M Descriptors in the Forthcoming Eighth Edition of the TNM Classification of Lung Cancer

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Introduction

The aim of this study is to analyze all metastatic (M) categories of the current tumor, node, and metastasis (TNM) classification of lung cancer with the objective of providing suggestions for modifications of the M component in the next edition of the TNM classification for lung cancer.

Methods

The new International Association for the Study of Lung Cancer lung cancer database was created from 94,708 patients diagnosed as having lung cancer between 1999 and 2010. Including further patients submitted through the electronic data capture system to Cancer Research and Biostatistics until 2012, all together 1059 non–small-cell lung cancer 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 (metastases within the chest cavity) descriptors. However, when M1b (distant metastases outside the chest cavity) were assessed according to the number of metastases, tumors with a single metastasis in a single organ had significantly better prognosis than those with multiple metastases in one or several organs.

Conclusions

In this revision of the TNM classification, cases with pleural/pericardial effusions, 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. Multiple lesions 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 non-smallcell lung cancer in the future.

Key Words

Lung cancer
Non-small-cell lung cancer
Staging
Metastases

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Disclosure: Wilfried Ernst Erich Eberhardt has declared to have received honoraria for advisory board function and educational lectures from Eli Lilly. His institution has received a research grant for an Investigator Initiated Trial from Eli Lilly. John Crowley has declared that his work is funded by the International Association for the Study of Lung Cancer (IASLC) and has received grants and support to travel from the IASLC. Alan Mitchell has declared that his work is funded by the International Association for the Study of Lung Cancer (IASLC) and has received grants and support to travel from the IASLC.

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Members of International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee, Advisory Board, and Participating Institutions are listed in Appendix.