Comparison Between Lymph Node Station- and Zone-Based Classification: An Extended Analysis With the Ninth Edition TNM
Shia Kim1, Geun Dong Lee1, Sehoon Choi1
1Department of Thoracic and Cardiovascular Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
JTO Clinical and Research Reports
|June 4, 2026
Summary
Zone-based lymph node classification offers improved prognostic accuracy for non-small cell lung cancer (NSCLC) compared to the traditional station-based system. This approach better stratifies patient outcomes and may refine future TNM staging.
Area of Science:
- Thoracic Oncology
- Surgical Pathology
- Cancer Staging
Background:
- The TNM classification for lung cancer uses lymph node (LN) stations to stage N2 disease.
- Current station-based staging may not fully capture prognostic differences within N2 disease.
Purpose of the Study:
- To compare the prognostic performance of a zone-based versus a station-based lymph node classification system in non-small cell lung cancer (NSCLC).
Main Methods:
- Retrospective analysis of 11,047 NSCLC patients undergoing curative resection and systematic LN dissection.
- Lymph node stations were grouped into anatomical zones (peripheral, hilar, mediastinal, aortopulmonary, subcarinal).
- Overall survival (OS) and freedom from recurrence (FFR) were analyzed using Kaplan-Meier and Cox regression.
Main Results:
- Both systems stratified OS and FFR, but zone-based classification showed clearer separation between N2a and N2b groups.
- Zone-based N2b had higher hazard ratios, and model fit was slightly better with the zone-based system.
- 28.8% of patients with station-based N2b were reclassified as zone-based N2a, indicating prognostic heterogeneity.
Conclusions:
- Zone-based lymph node classification provides improved prognostic discrimination for NSCLC compared to station-based grouping.
- This zone-based system may enhance future refinements of the TNM nodal staging system for lung cancer.
