Comparison of the 7th and proposed 8th editions of the AJCC/UICC TNM staging system for non-small cell lung cancer undergoing radical surgery

The present study aims to compare the 7^th and the proposed 8^th edition of the AJCC/UICC TNM staging system for NSCLC in a cohort of patients from a single institution. A total of 408 patients with NSCLC who underwent radical surgery were analyzed retrospectively. Survivals were analyzed using the Kaplan -Meier method and were compared using the log-rank test. Multivariate analysis was performed by the Cox proportional hazard model. The Akaike information criterion (AIC) and C-index were applied to compare the two prognostic systems with different numbers of stages. The 7^th AJCC T categories, the proposed 8^th AJCC T categories, N categories, visceral pleural invasion, and vessel invasion were found to have statistically significant associations with disease-free survival (DFS) on univariate analysis. In the 7^th edition staging system as well as in the proposed 8^th edition, T categories, N categories, and pleural invasion were independent factors for DFS on multivariate analysis. The AIC value was smaller for the 8^th edition compared to the 7^th edition staging system. The C-index value was larger for the 8^th edition compared to the 7^th edition staging system. Based on the data from our single center, the proposed 8^th AJCC T classification seems to be superior to the 7^th AJCC T classification in terms of DFS for patients with NSCLC underwent radical surgery.