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

We aimed to elucidate prognostic markers of node-positive gastric cancers with a focus on examined lymph nodes and lymph node ratio.

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.

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.

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.