Higher Numbers of Examined Lymph Nodes Are Associated with Increased Survival in Resected, Treatment-Naïve, Node-Positive Esophageal, Gastric, Pancreatic, and Colon Cancers

Background or Purpose: The role of extended lymphadenectomy as part of resection for lymph node (LN)–positive gastrointestinal (GI) malignancies remains controversial with no clear clinical guidance. The purpose of this retrospective study is to determine whether the number of LNs examined as part of GI malignancy resections affects overall survival (OS) among patients with node-positive esophageal, gastric, pancreatic, and colon cancers. Methods: Participants with LN-positive GI cancers who were diagnosed between 2004 and 2015 and underwent oncologic resections were selected from National Cancer Database (NCDB). The primary predictor was the number of examined LNs categorized in tertiles. The effect on OS was measured by hazard ratio (HR) derived from multivariate Cox regression analyses. Results: From 2004 to 2015, 1877, 10,086, 18,193, and 102,500 patients with LN-positive esophageal, gastric, pancreatic, and colon adenocarcinomas who did not receive neoadjuvant treatment and underwent oncologic tumor resection were registered in the NCDB. Using multivariate Cox proportional hazard modeling, greater LNs examined in surgically resected LN-positive GI cancers were found to be associated with increased OS for all histologies. This association was the strongest (as compared to the lowest tertile) for gastric cancer (middle tertile: HR = 0.91, 95% CI, 0.86–0.96, p = 0.001; highest tertile: HR = 0.73, 95% CI, 0.69–0.78, p < 0.001), followed by colon (highest tertile: HR = 0.86, 95% CI, 0.84–0.88, p < 0.001), esophageal (highest tertile: HR = 0.83, 95% CI, 0.72–0.95, p = 0.01), and pancreatic (highest tertile: HR = 0.93, 95% CI, 0.89–0.98, p = 0.002) cancers. Discussion and Conclusion: In patients with surgically resected node-positive GI malignancies who did not receive neoadjuvant systemic therapy, a higher number of examined LNs is associated with increased OS. This association is the strongest for gastric cancer, followed by colon, esophageal, and pancreatic cancers respectively.