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Prognostic impact of the N2 subclassification and stage migration in the ninth edition of the TNM classification in surgically resected lung cancer

  • 0Department of Thoracic Surgical Oncology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Japan.
Lung +

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January 1, 2025

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January 1, 2025

View abstract on PubMed

Summary

This summary is machine-generated.

The ninth edition of lung cancer staging refines N2 classification, impacting stage III prognosis. While the new TNM staging shows some survival differences, predicting N2 status preoperatively remains challenging, leading to a smaller OS gap in Stage III.

Area Of Science

  • Thoracic oncology
  • Cancer staging
  • Surgical oncology

Background

  • The TNM classification for lung cancer is periodically updated to reflect evolving understanding of disease.
  • The ninth edition introduced subdivisions for N2 (single-station N2a vs. multiple-station N2b) and adjusted stage groupings for II-III, potentially altering patient prognoses.

Purpose Of The Study

  • To validate the prognostic impact of the ninth edition's TNM classification for lung cancer, specifically the N2 subdivisions.
  • To assess the effects of stage migration on prognosis within pathological stages due to the revised TNM criteria.

Main Methods

  • Analysis of overall survival (OS) in 1,754 surgically resected lung cancer patients based on the new pathological N (pN) status and pathological stages.
  • Comparison of clinical characteristics between pN2a and pN2b groups.
  • Evaluation of survival differences for downstaged and upstaged patients.

Main Results

  • The OS for pN2a patients showed a non-significant trend towards being better than pN2b patients (p=0.083).
  • No significant differences in clinical characteristics were observed between pN2a and pN2b groups.
  • Downstaged patients did not show significantly different OS compared to others in their new stages, but upstaged patients (T3N2bM0) had significantly better OS (p<0.001).
  • The 5-year OS for Stage IIIA and IIIB decreased and increased, respectively, in the ninth edition compared to the eighth, narrowing the survival gap.

Conclusions

  • The N2 subclassification in the ninth edition TNM staging influences survival stratification but preoperative prediction of pN2 status is difficult.
  • The revised TNM staging resulted in a smaller OS difference within Stage III compared to the eighth edition due to complex stage migration effects.

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