Lymph node yield and its impact on survival outcomes: a retrospective multicenter cohort study from Denmark.

The prognostic value of lymph node (LN) yield in esophageal and gastric cancer remains controversial, especially in the context of modern perioperative treatment. This multicenter Danish cohort study evaluates the association between LN yield and survival outcomes. This study included 3092 patients who underwent curative-intent resection for esophageal (n = 2402) or gastric cancer (n = 690) between 2013 and 2021 at four Danish upper GI centers. All cases were registered in the Danish Esophagogastric Cancer Group database, covering 99% of all Danish esophageal and gastric cancer cases. Patients were stratified by nodal status (pN0/pN+) and categorized into five LN yield groups. Survival analyses were performed using Kaplan-Meier curves and multivariable Cox regression. In node-negative esophageal cancer, higher LN yields (20-29, 30-39, and 40+) were significantly associated with improved survival (hazard ratio: 0.47-0.58, P < 0.001) compared with the reference group (16-19). No survival benefit was seen beyond 16-19 nodes in node-positive esophageal or gastric cancers. Perioperative chemotherapy improved survival in node-positive esophageal cancer but had no effect in node-negative esophageal and gastric cancer. Discrepancies between clinical and pathological nodal staging were frequent and influenced both survival estimates and treatment allocation. LN removal was associated with survival in esophageal and gastric cancer. Node-negative patients showed increased survival if ≥20 nodes were removed, while node-positive esophageal cancer and gastric cancer patients showed no difference in survival beyond 16-19. Lastly, discrepancies between clinical and pathological staging underscore the need for more accurate preoperative diagnostics and highlight the impact of modern perioperative chemotherapy.