Prognostic significance of the total number of harvested lymph nodes for lymph node-negative gastric cancer patients

Background: The relationship between the number of harvested lymph nodes (HLNs) and prognosis of gastric cancer patients without an involvement of lymph nodes has not been well-evaluated. The objective of this study is to further explore this issue. Methods: We collected data from 399 gastric cancer patients between November 2006 and October 2011. All of them were without metastatic lymph nodes. Results: Survival analyses showed that statistically significant differences existed in the survival outcomes between the two groups allocated by the total number of HLNs ranging from 16 to 22. Therefore, we adopted 22 as the cut-off value of the total number of HLNs for grouping (group A: HLNs <22; group B: HLNs >= 22). The intraoperative and postoperative characteristics, including operative blood loss (P=0.096), operation time (P=0.430), postoperative hospital stay (P=0.142), complications (P=0.552), rate of reoperation (P=0.966) and postoperative mortality (P=1.000), were comparable between the two groups. T-stage-stratified Kaplan-Meier analyses revealed that the 5-year survival rate of patients at the T4 stage was better in group B than in group A (76.9% vs. 58.5%; P=0.004). An analysis of multiple factors elucidated that the total number of HLNs, T stage, operation time and age were independently correlated factors of prognosis. Conclusions: Regarding gastric cancer patients without the involvement of lymph nodes, an HLN number >= 22 would be helpful in prolonging their overall survival, especially for those at T4 stage. The total number of HLNs was an independent prognostic factor for this population of patients.