Validation of the Stage Groupings in the Eighth Edition of the TNM Classification for Lung Cancer

Abstract

Introduction: The aim of this study was to validate stage groupings in the eighth edition of the TNM classification in an independent Chinese cohort.

Methods: We retrospectively analyzed a total of 3599 patients with pathological stage IA to IIIA (seventh edition of the TNM) NSCLC who underwent surgical treatment in two surgical centers in the People's Republic of China between 2005 and 2012. All patients were reclassified according to the eighth edition of the TNM classification. Survival was compared between adjacent stage groupings by using a log-rank test and a Cox regression model. R² was calculated to evaluate the discrimination of the two TNM stage classifications.

Results: The median follow-up time was 48.7 months. According to the eighth edition of the TNM classification, the overall survival (OS) of adjacent stage groupings showed significant differences except for IA3 vs. IB. The eighth edition of the TNM classification yielded a slightly higher R² than the seventh edition (0.172 vs. 0.162).

Conclusions: This study provided an external validation of the stage groupings in the eighth edition of the TNM classification for lung cancer among surgically treated Chinese patients with NSCLC.

Keywords: External validation; Non–small cell lung cancer; TNM classification; Thoracic surgery.