Lymph node staging systems in patients with gastric cancer treated with D2 resection plus adjuvant chemotherapy

Background: The optimal nodal staging scheme for gastric cancer remains unsettled. We compared the prognostic performances of the metastatic lymph node, lymph node ratio, and log odds of metastatic lymph nodes based on nomograms among 801 patients with D2-resected gastric cancer treated with adjuvant chemotherapy. Methods: When assessed as a continuous covariate, each nodal staging variable was incorporated into a prognostic nomogram with other significant prognosticators to predict the 5-year overall survival. The discriminatory abilities of the nomograms were compared using the concordance index. Patients were divided into subgroups using each nomogram, and the prognostic homogeneity of the nomograms was assessed using the Kaplan-Meier method with log-rank tests. Results: The discriminatory abilities of the three nomograms were comparable (P > 0.05 for all pairwise comparisons). However, for patients within each lymph node ratio subgroup, overall survival was homogenous when stratified by subgroups of the other two staging schemes, while it differed significantly among the different lymph node ratio subgroups for patients within some of the other two staging subgroups. Conclusion: The lymph node ratio-based staging scheme performs the best for the prediction of survival in patients with locally advanced gastric cancer treated with D2 resection followed by adjuvant chemotherapy.