The IASLC Mesothelioma Staging Project: Proposals for the M Descriptors and for Revision of the TNM Stage Groupings in the Forthcoming (Eighth) Edition of the TNM Classification for Mesothelioma
Journal of Thoracic Oncology 2016 September 27 [Epub ahead of print] [Link]
Rusch VW, Chansky K, Kindler HL, Nowak AK, Pass HI, Rice DC, Shemanski L, Galateau-Sallé F, McCaughan BC, Nakano T, Ruffini E, van Meerbeeck JP, Yoshimura M; Staging and Prognostic Factors Committee, Advisory Boards and Participating Institutions
Abstract
INTRODUCTION:
The metastasis (M) component and TNM stage groupings for malignant pleural mesothelioma (MPM) have been empiric. The International Association for the Study of Lung Cancer developed a multinational database to propose evidence-based revisions for the 8th editions of the tumor, node and metastases (TNM) classification of MPM.
METHODS:
Data from 29 centers were submitted either electronically or by transfer of existing institutional databases. The M component, as it currently stands was validated by confirming sufficient discrimination (by Kaplan Meier) with respect to overall survival (OS) between the clincal (c)M0 and cM1 categories. Candidate stage groups were developed using a recursive partitioning and amalgamation (RPA) algorithm applied to all cM0 cases.
RESULTS:
Of 3,519 submitted cases, 2,414 were analyzable and 84 cases were cM1. Median OS for cM1 was 9.7 months versus 13.4 months (p=.0013) for the locally advanced (T4 or N3) cM0 cases, supporting inclusion of only cM1 in the stage IV group. Exploratory analyses suggest a possible difference in OS for single versus multiple site cM1. RPA generated survival tree on the OS outcomes restricted to cM0 with newly proposed (8th edition) T and N components, indicates that optimal stage groupings for the 8th edition will be: stage IA (T1N0), stage IB (T2-3N0), stage II (T1-2N1), stage IIIA (T3N1), stage IIIB (T1-3N2 or any T4), and stage IV (any M1).
CONCLUSIONS:
This first evidence-based revision of the TNM classification for MPM leads to substantial changes in the T and N components and the stage groupings.
