Benchmarks for nodal yield and ratio for node-positive gastric cancer

Background: We aimed to elucidate prognostic markers of node-positive gastric cancers with a focus on examined lymph nodes and lymph node ratio. Methods: Patients treated with curative-intent gastrectomy at The University of Texas MD Anderson Cancer Center from 1995-2019 were evaluated. Patients with non-metastatic, node-positive gastric cancers were considered for analysis. Results: Of 775 patients, 281 met the inclusion criteria. The mean age was 58 years, 61% were male, 51% were White, 65% received preoperative therapy, and 71% of tumors were located in the gastric body. The median overall survival was 3.6 years, and 1-, 5-, and 10-year overall survival rates were 91%, 41%, and 29%, respectively. pN3 category was associated with worse overall survival (hazard ratio 1.79, P = .001) and recurrence-free survival (hazard ratio 1.92, P = .004). Nodal burden was associated with aggressive biologic traits in primary tumors, including higher rates of lymphovascular and perineural invasion and lower preoperative therapy response rates. By receiver-operative characteristic analysis, threshold values of >30 examined lymph nodes and <30% lymph node ratio were most discriminant for overall survival. On adjusted analysis, positive margins, additional organ resection, <30 examined lymph nodes, and >30% lymph node ratio were associated with worse recurrence-free survival and overall survival. Among patients with high node burden (pN3), <30 examined lymph nodes remained significant on adjusted survival analysis. Conclusion: Greater than or equal to 30 examined lymph nodes and <30% lymph node ratio were significantly associated with longer recurrence-free survival and overall survival, independent of lymphadenectomy type. These prognostic benchmarks should be considered in the surgical management of gastric cancer in the United States. (c) 2021 Elsevier Inc. All rights reserved.