Prognostic significance of a pathological response in metastatic lymph nodes of patients with gastric cancer who underwent neoadjuvant chemotherapy followed by surgery.

ABSTRACT

PURPOSE: To grade the pathological response of lymph nodes (LNs) to neoadjuvant chemotherapy (NAC) in patients with locally advanced gastric cancer (LAGC) and investigate its prognostic significance. METHODS: This retrospective study included 196 patients who underwent NAC, followed by radical gastrectomy for LAGC between January 2010 and October 2019. Pathological responses were evaluated based on the proportion of residual tumor cells within the tumor area in the primary tumor (PT) and LNs and included the following categories 1a (0%), 1b (< 10%), 2 (10-50%), and 3 (> 50%). RESULTS: Among 166 patients with clinically node-positive disease, 38/27/39/62 were classified as having LN regression grade (LRG) 1a/1b/2/3, respectively. Compared to LN non-responders (LRG 2 or 3), LN responders (LRG 1a or 1b) had significantly higher 5-year overall survival (72.5% vs. 19.0%, P < 0.001) and recurrence-free survival rates (67.8% vs. 22.2%, P < 0.001), irrespective of PT response. Furthermore, a multivariate analysis revealed that the LN response was an independent risk factor for the overall survival (hazard ratio [HR] 0.417, 95% confidence interval [CI] 0.181-0.962, P = 0.040) and recurrence-free survival (HR 0.490, 95% CI 0.242-0.991, P = 0.047), but not the PT response (P > 0.05). CONCLUSIONS: The pathological LN response may be a reliable prognostic prediction tool in patients with LAGC who received NAC.