Total Lymph Node Yield Is Associated with Prolonged Survival after Neoadjuvant Chemotherapy in ypN0 Gastric Cancer Patients

Abstract

Introduction: Lymph node status after neoadjuvant chemotherapy (NAC) plays the main role in predicting the survival of gastric cancer (GC) patients who underwent curative gastrectomy after NAC. NAC can reduce the number of involved lymph nodes. However, it is unknown whether other variables are associated with the survival outcomes for ypN0 GC patients. It is unknown whether lymph node yield (LNY) has prognostic value in ypN0 GC patients treated with NAC plus surgery. Methods: In this retrospective study, we reviewed the data of patients treated with NAC plus gastrectomy and identified those with ypN0 disease. The LNY cut-off was calculated using the X-tile program to determine the greatest actuarial survival difference. Patients were categorized into the downstaged N0 (cN+/ypN0) and natural N0 (cN0/ypN0) groups based on nodal status. Multivariate analysis was used to identify the prognostic factors and the association between LNY and prognosis. Results: A total of 211 GC patients with ypN0 status were included. The optimal LNY cut-off was 23. Kaplan-Meier analysis revealed no significant difference in overall survival between the natural and downstaged N0 groups, while ypN0 GC patients with an LNY of ≥24 had significantly longer overall survival than those with an LNY of ≤23. Univariate analysis identified that LNY, cT stage, tumor location, ypT stage, perineural invasion, lymphovascular invasion, tumor size, Mandard tumor regression grade, and extent of gastrectomy were significantly associated with overall survival. Multivariate analysis confirmed that perineural invasion (hazard ratio, 4.246; p < 0.001), lymphovascular invasion (hazard ratio, 2.694; p = 0.048), and an LNY of ≥24 (hazard ratio, 0.394; p = 0.011) were independent prognostic factors. Conclusions: Patients with natural and downstaged ypN0 GC had similar overall survival after NAC. LNY was an independent prognostic factor in these patients, and an LNY of ≥24 predicted prolonged overall survival.