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. 2024 May;19(5):786-802.
doi: 10.1016/j.jtho.2024.01.019. Epub 2024 Feb 4.

The International Association for the Study of Lung Cancer Staging Project for Lung Cancer: Proposals for the Revision of the M Descriptors in the Forthcoming Ninth Edition of the TNM Classification for Lung Cancer

Kwun M Fong  1 , Adam Rosenthal  2 , Dorothy J Giroux  2 , Katherine K Nishimura  2 , Jeremy Erasmus  3 , Yolande Lievens  4 , Mirella Marino  5 , Edith M Marom  6 , Paul Martin Putora  7 , Navneet Singh  8 , Francisco Suárez  9 , Ramon Rami-Porta  10 , Frank Detterbeck  11 , Wilfried E E Eberhardt  12 , Hisao Asamura  13 ; Members of the International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee, Members of the Advisory Boards, and Participating Institutions of the Lung Cancer Domain
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Free article

The International Association for the Study of Lung Cancer Staging Project for Lung Cancer: Proposals for the Revision of the M Descriptors in the Forthcoming Ninth Edition of the TNM Classification for Lung Cancer

Kwun M Fong et al. J Thorac Oncol. 2024 May.
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Erratum in

Abstract

Introduction: This study analyzed all metastatic categories of the current TNM classification of NSCLC to propose modifications of the M component in the next edition (ninth) of the classification.

Methods: A database of 124,581 patients diagnosed between 2011 and 2019 was established; of these, 14,937 with NSCLC in stages IVA to IVB were available for this analysis. Overall survival was calculated using the Kaplan-Meier method, and prognosis was assessed using multivariable-adjusted Cox proportional hazards regression.

Results: The eighth edition M categories revealed good discrimination in the ninth edition data set. Assessments revealed that an increasing number of metastatic lesions were associated with decreasing prognosis; because this seems to be a continuum and adjustment for confounders was not possible, no specific lesion number was deemed appropriate for stage classification. Among tumors involving multiple metastases, decreasing prognosis was found with an increasing number of organ systems involved. Multiple assessments, including after adjustment for potential confounders, revealed that M1c patients who had metastases to a single extrathoracic organ system were prognostically distinct from M1c patients who had involvement of multiple extrathoracic organ systems.

Conclusions: These data validate the eighth edition M1a and M1b categories, which are recommended to be maintained. We propose the M1c category be divided into M1c1 (involvement of a single extrathoracic organ system) and M1c2 (involvement of multiple extrathoracic organ systems).

Keywords: Lung cancer; Metastases; Non–small cell lung cancer; Stage IV lung cancer; Stage classification.

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Conflict of interest statement

Disclosure Dr. Fong reports receiving grants and contracts from MRFF EPCDR, NHMRC Ideas Grant, MRFF Next Generation Clinical Researchers Program, NHMRC; receiving funds from UpToDate as reviewer and Cochrane Clinical Answers as reviewer; and receiving equipment support from Olympus and Mevis Veolity. Mr. Rosenthal reports receiving fees for service from IASLC to complete work associated with publication. Ms. Giroux reports receiving fees for service from IASLC to complete work associated with publication. Dr. Nishimura reports receiving fees for service from IASLC to complete work associated with publication. Dr. Erasmus reports receiving honoraria from Canadian Association of Radiologists. Dr. Lievens reports receiving grants and contracts for the ImmunoSABR EU Project, HERO-VBHC chair; consulting fees from AstraZeneca; and honoraria from Merck Sharp & Dohme. Dr. Marom reports receiving honoraria from Boehringer Ingelheim, Merck, and AstraZeneca. Dr. Putora reports receiving grants or contracts from Bayer, Takeda, and AstraZeneca. Dr. Suárez reports receiving consulting fees from AstraZeneca and Roche; honoraria from AstraZeneca. The remaining authors declare no conflict of interest.

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