The retrieval of at least 25 lymph nodes should be essential for advanced gastric cancer patients with lymph node metastasis: A retrospective analysis of single-institution database study design: Cohort study

Background: Recently, increased evidence have shown that the better prognosis of gastric cancer (GC) patients was associated with the larger number of retrieved lymph nodes (RLNs), but the optimal number of RLNs remains controversial. In the present study, we investigated whether adequate LN retrieval (>= 15) was necessary to evaluate the prognosis of patients and attempted to propose an appropriate cutoff-point for the number of RLNs. Methods: We reviewed 2246 GC patients who underwent radical gastrectomy in our research institution between January 1986 and January 2008. All patients were divided into several groups based on the number of RLNs. The prognostic outcomes of different patient groups were compared and clinicopathologic features were analyzed. Results: In the present study, our results indicated that >= 15 RLNs showed a better survival outcome than inadequate LN retrieval (< 15), regardless of the node-negative or node-positive GC patients (P < 0.001). For the more advanced GC patients (T2-T4 stage, N1-N3 stage, and stage II-stage III), the retrieval of 25-29 LNs could provide a better survival benefit compared with < 25 or >= 30 RLNs (P < 0.05). In addition, for the patients who underwent proximal or total gastrectomy, the superior prognosis was still observed in the patient group with 25-29 RLNs. Conclusion: The minimal goal of 15 RLNs may not be enough to accurately evaluate prognosis of all patients and at least 25 RLNs should be necessary for advanced GC patients with lymph node metastasis.