Comparison of the 6th and 7th editions of the UICC TNM staging system for gastric cancer: results of a Chinese single-institution study of 1,503 patients.

AIM: To evaluate the prognostic efficacy of the 7th edition tumor-node-metastasis (TNM) classification compared with the 6th edition in gastric cancer patients. METHODS: A total of 1,503 gastric cancer patients undergoing surgical resection were staged using the 6th and 7th edition staging systems. Homogeneity, discriminatory ability, and monotonicity of gradients of the two systems were compared using linear trend χ(2), likelihood ratio χ(2) statistics, and Akaike information criterion (AIC) calculations. RESULTS: Significant differences in 5-year survival rates were observed for the T, N, and M subgroups using the 7th edition system, except for stage N2 and N3 patients in the 6th edition system. There were no significant differences in survival between IB and IIA in the 7th edition system. Patients with stage IV disease due to T4/N3 in the 6th edition system who were downstaged to stage III in the 7th edition system had significantly better survival than those who remained at stage IV. The 7th edition system had higher linear trend and likelihood ratio χ(2) scores, and smaller AIC values compared with those for the 6th edition, which represented the optimum prognostic stratification. CONCLUSIONS: Our study suggests that the 7th edition system performs better than the 6th edition in several aspects.