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

Abstract

PurposeGuidelines 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 MethodsThe 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.ResultsOf 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).ConclusionsIn 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.

Retrospective Evaluation of Factors Affecting Lymph Node Retrieval Following Gastrectomies with Oncologic Intent

“…16,17 Mirkin et al published a study relying on the National Cancer Data Base, which captures over 70% of the newly diagnosed cancer patients in the United States. 10 In their study, as many as 60% of the patients undergoing gastrectomy for gastric cancer had 15 lymph nodes or less examined by the pathologist. CI, confidence interval; HGD, high-grade dysplasia.…”

“…8,9 Still, in a significant proportion of gastric resections the goal of pathologically examining at least 15 lymph nodes is not achieved. 10 While there is an agreement as to the minimum number of lymph nodes required for appropriate assessment, only a few studies have evaluated the factors associated with achieving this goal. This study's main objective was to examine how many surgeries indeed succeed in resecting an adequate number of lymph nodes and to evaluate possible factors associated with inadequate lymph node resection.…”

Comparison of gastric cancer survival after R0 resection in the US and China

“…12 The most likely contributor is the much greater number of lymph nodes retrieved at FMUUH (median 32 vs 16 at BCH). Greater lymph node retrieval has been associated with better survival in numerous studies, 15,16 including one in China. 17 Another key difference is that the prior study included patients with fewer than 15 LNs retrieved, which may have resulted in underestimation of N category preferentially among Chinese cases, where retrieval of few lymph nodes was more frequent.…”

“…[12] The most likely contributor is the much greater number of lymph nodes retrieved at FMUUH (median 32 vs. 16 at BCH). Greater lymph node retrieval has been associated with better survival in numerous studies,[15,16] including one in China. [17]…”

ASO Author Reflections: Number of Examined Lymph Nodes in Gastric Cancer Resection Following Neoadjuvant Chemotherapy

“…Prior work by Mirkin et al demonstrated that an inadequate lymphadenectomy of fewer than 11 lymph nodes among patients undergoing neoadjuvant therapy resulted in significantly worse survival for patients with stage III gastric cancer; however, in patients who underwent surgical resection first-line therapy, inadequate lymphadenectomy was also associated with worse survival outcomes in stage I and II disease, suggesting that inadequate lymphadenectomy has prognostic implications regardless of initial therapy. 2 An institutional analysis by Ho et al 3 in patients with surgically resected esophageal cancer who underwent NACT demonstrated that an increase in the number of lymph nodes retrieved (more than 21) was associated with improved survival, suggesting that utilization of NACT may influence the number of regional lymph nodes necessary for optimal prognostication. Conceptually, NACT may yield complete pathologic responses in lymph nodes, which may increase the number of evaluated lymph nodes necessary for improved prognostication, but how this influences lymph node retrieval in patients with gastric cancer specifically, remains understudied.…”