Clinical Significance of Residual Lymph Node Metastasis in Predicting Recurrence After Preoperative Chemotherapy and Surgery for Gastric Cancer

Neoadjuvant chemotherapy is gaining recognition for its potential to improve survival outcomes, with combined neoadjuvant and adjuvant therapies under investigation. However, the prognostic significance of post-chemotherapy pathological staging (ypStage) on recurrence-free survival (RFS) remains unclear. This study aimed to evaluate the utility of ypStage, ypT, ypN classification, and histological response rate in predicting recurrence after gastrectomy. This retrospective study included 125 patients who underwent radical gastrectomy after preoperative chemotherapy at the Kanagawa Cancer Center between January 2007 and November 2019. RFS was analyzed based on ypStage, ypT, ypN classification, and histological response rate, with prognostic factors also assessed. The 5-year RFS rates were 81.6% for ypStage I, 49.0% for ypStage II, and 42.9% for ypStage III. Significant differences were observed between ypStage I and ypStage II (p=0.025) but not between ypStage II and ypStage III (p =0.633). In ypStage II/III cases, the 5-year RFS rate was significantly higher for ypN0/1/2 (55.4%) compared to ypN3 (21.5%) (p=0.003). ypN was selected as an independent predictor for relapse in multivariate analysis. ypStage effectively predicts recurrence in ypStage I cases after preoperative chemotherapy and surgery for gastric cancer. However, prognosis in patients with ypStage II/III is better stratified using the ypN classification, particularly ypN3.