The International Association for the Study of Lung Cancer Mesothelioma Staging Project: Proposals for Revisions of the "T" Descriptors in the Forthcoming Ninth Edition of the TNM Classification for Pleural Mesothelioma

Ritu R Gill; Anna K Nowak; Dorothy J Giroux; Megan Eisele; Adam Rosenthal; Hedy Kindler; Andrea Wolf; Robert T Ripley; Andre Billé; David Rice; Isabelle Opitz; Andreas Rimner; Marc de Perrot; Harvey I Pass; Valerie W Rusch; members of the International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee, Advisory Boards and Participating Institution

doi:10.1016/j.jtho.2024.03.007

The International Association for the Study of Lung Cancer Mesothelioma Staging Project: Proposals for Revisions of the "T" Descriptors in the Forthcoming Ninth Edition of the TNM Classification for Pleural Mesothelioma

J Thorac Oncol. 2024 Mar 21:S1556-0864(24)00086-8. doi: 10.1016/j.jtho.2024.03.007. Online ahead of print.

Authors

Ritu R Gill¹, Anna K Nowak², Dorothy J Giroux³, Megan Eisele³, Adam Rosenthal³, Hedy Kindler⁴, Andrea Wolf⁵, Robert T Ripley⁶, Andre Billé⁷, David Rice⁸, Isabelle Opitz⁹, Andreas Rimner¹⁰, Marc de Perrot¹¹, Harvey I Pass¹², Valerie W Rusch¹³; members of the International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee, Advisory Boards and Participating Institution

Affiliations

¹ Department of Radiology, Beth Israel Deaconess Medical Center, Boston, Massachusetts. Electronic address: rgill@bidmc.harvard.edu.
² National Centre for Asbestos Related Diseases, Medical School, University of Western Australia, Crawley, Western Australia, Australia.
³ Cancer Research And Biostatistics, Seattle, Washington.
⁴ Department of Medicine, Section of Hematology/Oncology, University of Chicago, Illinois.
⁵ Department of Cardiothoracic Surgery, Icahn School of Medicine at Mount Sinai, New York, New York.
⁶ Department of Thoracic Surgery, Baylor College of Medicine, Houston, Texas.
⁷ Thoracic Surgery, Guy's Hospital, Thoracic Surgery, London, UK.
⁸ Thoracic Surgery, The University of Texas MD Anderson Cancer Center, Texas.
⁹ Department of Thoracic Surgery, University Hospital Zurich, Switzerland.
¹⁰ Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York.
¹¹ Thoracic Surgery, University Health Network, Toronto General Hospital & Princess Margaret Hospital, Toronto, Canada.
¹² Thoracic Surgery, NYU Langone Medical Center, New York.
¹³ Thoracic Surgery, Memorial Sloan Kettering Cancer Center, New York, New York.

PMID: 38521202
DOI: 10.1016/j.jtho.2024.03.007

Abstract

Introduction: The primary tumor (T) component in the eighth edition of pleural mesothelioma (PM) staging system is based on pleural involvement and extent of invasion. Quantitative assessment of pleural tumor has been found to be prognostic. We explored quantitative and qualitative metrics to develop recommendations for T descriptors in the upcoming ninth edition of the PM staging system.

Methods: The International Association for the Study of Lung Cancer prospectively collected data on patients with PM. Sum of maximum pleural thickness (Psum) was recorded. Optimal combinations of Psum and eighth edition cT descriptors were assessed using recursive binary splitting algorithm, with bootstrap resampling to correct for the adaptive nature of the splitting algorithm, and validated in the eighth edition data. Overall survival (OS) was calculated by the Kaplan-Meier method and differences in OS assessed by the log-rank test.

Results: Of 7338 patients submitted, 3598 were eligible for cT analysis and 1790 had Psum measurements. Recursive partitioning identified optimal cutpoints of Psum at 12 and 30 mm, which, in combination with extent of invasion, yielded four prognostic groups for OS. Fmax greater than 5 mm indicated poor prognosis. cT4 category (based on invasion) revealed similar performance to eighth edition. Three eighth edition descriptors were eliminated based on low predictive accuracy. Eighth edition pT descriptors remained valid in ninth edition analyses.

Conclusion: Given reproducible prognostication by Psum, size criteria will be incorporated into cT1 to T3 categories in the ninth edition. Current cT4 category and all pT descriptors will be maintained, with reclassification of fissural invasion as pT2.

Keywords: Clinical stage; Pleural mesothelioma; Staging; T component.