The IASLC Pleural Mesothelioma Staging Project: Proposal for Revision of the TNM Stage Groupings in the Forthcoming (Ninth) Edition of the TNM Classification for Pleural Mesothelioma

Anna K Nowak; Dorothy J Giroux; Megan Eisele; Adam Rosenthal; Andrea Bille; Ritu R Gill; Hedy L Kindler; Harvey I Pass; David Rice; R Taylor Ripley; Andrea Wolf; Joseph Friedberg; Katherine Nishimura; Valerie W Rusch; Members of the Staging and Prognostic Factors Committee, of the Advisory Boards and Participating Institutions

doi:10.1016/j.jtho.2024.05.002

The IASLC Pleural Mesothelioma Staging Project: Proposal for Revision of the TNM Stage Groupings in the Forthcoming (Ninth) Edition of the TNM Classification for Pleural Mesothelioma

J Thorac Oncol. 2024 May 9:S1556-0864(24)00207-7. doi: 10.1016/j.jtho.2024.05.002. Online ahead of print.

Authors

Anna K Nowak¹, Dorothy J Giroux², Megan Eisele², Adam Rosenthal², Andrea Bille³, Ritu R Gill⁴, Hedy L Kindler⁵, Harvey I Pass⁶, David Rice⁷, R Taylor Ripley⁸, Andrea Wolf⁹, Joseph Friedberg¹⁰, Katherine Nishimura², Valerie W Rusch¹¹; Members of the Staging and Prognostic Factors Committee, of the Advisory Boards and Participating Institutions

Affiliations

¹ Medical School, the University of Western Australia. Electronic address: anna.nowak@uwa.edu.au.
² Cancer Research And Biostatistics, Seattle, Washington, USA.
³ Thoracic Surgery, Guy's Hospital, Thoracic Surgery, London, UK.
⁴ Department of Radiology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
⁵ Department of Medicine, Section of Hematology/Oncology, University of Chicago, Illinois, USA.
⁶ Thoracic Surgery, NYU Langone Medical Center, New York, USA.
⁷ Thoracic Surgery, The University of Texas MD Anderson Cancer Center, Texas, USA.
⁸ Department of Thoracic Surgery, Baylor College of Medicine, Houston, Texas, USA.
⁹ Department of Cardiothoracic Surgery, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
¹⁰ Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA.
¹¹ Thoracic Surgery, Memorial Sloan Kettering Cancer Center, New York, New York, USA.

PMID: 38734072
DOI: 10.1016/j.jtho.2024.05.002

Abstract

Introduction: The eighth edition of the tumor, node and metastases (TNM) classification of pleural mesothelioma (PM) saw substantial changes in T and N components and stage groupings. The International Association for the Study of Lung Cancer collected data into a multinational database in order to further refine this classification. This 9^th edition proposal incorporates changes proposed in the clinical (c)T component, but not the pathologic (p)T component, to include size criteria, and further refines TNM stage groupings for PM.

Methods: Data were submitted via electronic data capture (EDC) or batch transfer from institutional databases. Survival was measured from diagnosis date. Candidate stage groups were developed using a recursive partitioning and amalgamation (RPA) algorithm applied to all cM0 cases for clinical stage and subsequently for pathological stage. Cox models were developed to estimate survival for each stage group.

Results: Of 3598 submitted cases, 2192 were analyzable for overall cStage and 445 for overall pStage. RPA generated survival tree on OS outcomes restricted to cM0 with newly proposed (9^th edition) cT and cN component-derived optimal stage groupings of: stage I (T1N0), II (T1N1; T2N0), IIIA (T1N2; T2N1/2; any T3), IIIB (any T4), and IV (any M1). Although cT and pT descriptors are different in the 9^th edition, aligning pStage groupings with cStage produced better discrimination than retaining 8^th edition pStage groupings.

Conclusions: This revision of the clinical TNM classification for PM is the first to incorporate the measurement-based proposed changes in clinical T category. The pathological TNM aligns with clinical TNM.

Keywords: M component; Mesothelioma; N component; Pleural; Staging; T component.