External validation of a modified 8th AJCC TNM system for advanced gastric cancer: Long-term results in southern China.

BACKGROUND

The 8th edition of AJCC TNM staging manual for gastric cancer (GC) has been validated by several studies. A modified staging system based on it and total harvested number of lymph nodes (LNs; cutoff: 30) is suggested to improve predictive capacities for advanced GC. This study is designed to validate the modified method using a single-center database in Southern China.

METHODS

Clinical data from 684 GC patients with stage II and III according to the 7th edition between 2001 and 2012 were reviewed. A modified staging system was applied to restage the cohort. The three staging systems were compared in terms of prognostic performance on long-term survival.

RESULTS

The median follow-up period of this cohort was 52 (range, 6-180) months, with a median 5-year overall survival rate of 52.4%. Stage migration was observed in 159 (23.2%) patients according to the 8th edition of TNM staging, and another migration was observed in 108 (15.8%) patients according to the modified TNM staging system. Compared with the modified staging system, both 7th and 8th edition of AJCC TNM staging systems did not prove survival concordance on stage IIIA (7th edition) and stage IIIC (8th edition) when <30 LNs were examined. The survival performance between two AJCC staging systems had no significant improvement (c-index, 0.607 vs. 0.609), with the best prognostic stratification obtained using the modified staging method (c-index, 0.631).

CONCLUSIONS

The modified staging system on basis of the 8th AJCC classification and the number of harvested LNs could provide an optimal predictive capacities for advanced gastric cancer.