Comparison of 6th and 7th AJCC TNM staging classification for carcinoma of the stomach in China

Abstract

Background: The 7th edition of American Joint Committee on Cancer tumor-node-metastasis (AJCC TNM) staging system was put into use recently. The study aimed to evaluate its predictive ability on survival and compare the difference between the 6th and 7th editions of AJCC TNM system in gastric carcinoma.

Materials and methods: A total of 1000 gastric carcinoma patients receiving treatment in our center were selected for the analysis. Patients were staged using both the 6th and 7th editions AJCC TNM staging system. Survival analysis was performed with a Cox regression model.

Results: Of previous stage IV patients, 39.9% (112 of 281) migrated to a lower tier in the 7th edition. By setting the cutoff of positive lymph nodes as 0, 2, 6, and 15, the 7th edition strengthens the role of positive lymph nodes. Multivariable regression analysis showed that both 6th and 7th TNM stage systems were independent factors for overall survival. For lymph nodes negative patients, the 5-year overall survival for patients with fewer than 15 resected lymph nodes was significantly lower than those with more than 15.

Conclusions: AJCC 7th is not superior to AJCC 6th in predicting the 5-year overall survival rates of gastric adenocarcinoma patients. The definition of stage IV and the selection of cutoffs for MLNC in the AJCC 7th system is much more reasonable compared with the AJCC 6th system.