WCLC 2025 - Posters & ePosters-P2.05.17 European Single-Center Validation of the 9Th TNM Staging System in Over 3,300 Surgically Treated NSCLC Patients

P2.05.17 European Single-Center Validation of the 9Th TNM Staging System in Over 3,300 Surgically Treated NSCLC Patients

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This European single-center retrospective study assessed the prognostic performance of the newly introduced 9th edition of the IASLC TNM staging system for surgically treated non-small cell lung cancer (NSCLC) patients, comparing it with the previous 8th edition. The analysis included 3,313 patients with stage I–IIIB NSCLC who underwent anatomical resection and systematic lymph node dissection between 2010 and 2022 at a certified lung cancer center.<br /><br />The 9th TNM edition introduces a subdivision of the N-descriptor into N2a and N2b categories, aiming to refine nodal staging. Upon reclassification, 91.4% of patients' stages remained unchanged, while 6.8% were down-staged and 1.8% were up-staged, mainly due to the revised nodal descriptors. Baseline characteristics did not significantly differ between patients with stage changes and the broader cohort.<br /><br />Prognostic ability was evaluated using overall survival comparisons through Kaplan-Meier analysis, and model performance was assessed by Akaike Information Criterion (AIC), R², and Concordance index (C-index). Both editions showed comparable predictive accuracy: AIC was 21,733 vs. 21,146, R² was 0.362 vs. 0.417, and C-index was 0.625 vs. 0.627 (p=0.002 for both), indicating a modest improvement in the 9th edition.<br /><br />The study concludes that the 9th TNM edition modestly improves prognostic discrimination while maintaining overall stability of the staging framework. The limited stage migration suggests the new system refines rather than overhauls staging, supporting its clinical adoption for better prognostic stratification in NSCLC surgical patients.

Asset Subtitle

Inna Schott

Meta Tag

Speaker Inna Schott

Topic Pulmonology and Staging

Keywords

IASLC TNM staging system

9th edition

non-small cell lung cancer

NSCLC

prognostic performance

N2a and N2b nodal descriptors

stage migration

Kaplan-Meier analysis

Akaike Information Criterion

surgical resection