Increasing the Number of Examined Lymph Nodes is a Prerequisite for Improvement in the Accurate Evaluation of Overall Survival of Node-Negative Gastric Cancer Patients.

BACKGROUND: This study aims to elucidate whether increasing the number of examined lymph nodes (NELN) is mandatory for the accurate prognosis of node-negative gastric cancer (GC) patients after curative gastrectomy in Eastern countries (China and Japan).

METHODS: The clinicopathological data of 2455 GC patients (including 1137 node-negative cases) were included to demonstrate whether a minimum NELN is inevitable for guaranteeing the accurate prognosis of node-negative GC patients after curative gastrectomy.

RESULTS: Survival analyses revealed that the NELN significantly positively correlated with overall survival (p < 0.001) and was an independent prognostic predictor (hazard ratio 0.447; p = 0.025) of 1137 node-negative GC patients. Stratum analysis within the Kaplan-Meier method showed that sex, tumor size, and extent of lymphadenectomy did not affect the NELN in predicting the prognosis of all node-negative GC patients. Stage migration was mainly detected in the subgroup of node-negative GC Chinese patients who presented considerably lower mean NELN and more advanced staging than patients from Japan. The NELN was identified as the most intensively independent predictor of prognosis of 600 node-negative GC patients from China, with the smallest Akaike information criterion (176.964) and Bayesian information criterion values (194.552). These findings indicate that increasing the NELN is a prerequisite to guaranteeing precise TNM classification.

CONCLUSIONS: The NELN should be considered a mandatory requirement for improving the accuracy of prognostic evaluation of GC patients, especially for advanced-stage patients.