Greater Lymph Node Retrieval Improves Survival in Node-Negative Resected Gastric Cancer in the United States

PURPOSE: Guidelines in western countries recommend retrieving ≥15 lymph nodes (LNs) during gastric cancer resection. This study sought to determine whether the number of examined lymph nodes (eLNs), a proxy for lymphadenectomy, effects survival in node-negative disease. MATERIALS AND METHODS: The US National Cancer Database (2003–2011) was reviewed for node-negative gastric adenocarcinoma. Treatment was categorized by neoadjuvant therapy (NAT) vs. initial resection, and further stratified by eLN. Kaplan-Meier and Weibull models were used to analyze overall survival. RESULTS: Of the 1,036 patients who received NAT, 40.5% had ≤10 eLN, and most underwent proximal gastrectomy (67.8%). In multivariate analysis, greater eLN was associated with improved survival (eLN 16–20: HR, 0.71; P=0.039, eLN 21–30: HR, 0.55; P=0.001). Of the 2,795 patients who underwent initial surgery, 42.5% had ≤10 eLN, and the majority underwent proximal gastrectomy (57.2%). In multivariate analysis, greater eLN was associated with improved survival (eLN 11–15: HR, 0.81; P=0.021, eLN 16–20: HR, 0.73; P=0.004, eLN 21–30: HR, 0.62; P<0.001, and eLN >30: HR, 0.58; P<0.001). CONCLUSIONS: In the United States, the majority of node-negative gastrectomies include suboptimal eLN. In node-negative gastric cancer, greater LN retrieval appears to have therapeutic and prognostic value, irrespective of initial treatment, suggesting a survival benefit to meticulous lymphadenectomy.