Prognostic value of combined pathological response in primary tumor and lymph nodes after neoadjuvant chemoimmunotherapy for locally advanced gastric cancer.

[BACKGROUND] Inconsistent pathological responses between primary tumors and lymph nodes are frequently observed in patients with locally advanced gastric cancer (LAGC) undergoing neoadjuvant chemoimmunotherapy. However, limited studies have evaluated the prognostic significance of such discrepancies. This study aimed to investigate the prognostic value of combined pathological responses in the primary tumor and lymph nodes among patients with LAGC treated with neoadjuvant chemoimmunotherapy.

[METHODS] A retrospective study was conducted on 109 patients with LAGC who underwent radical surgery after neoadjuvant chemoimmunotherapy. The demographic and pathological characteristics were collected. Patients were classified into 4 groups based on the pathological responses of the primary tumor and lymph nodes, and the relevant clinicopathological features were compared. The overall survival was evaluated using Kaplan-Meier analysis.

[RESULTS] The rates of primary lymph node (ypN0), pathological complete response (pCR), and primary tumor pCR (ypT[pCR]) were 64.2% (46/109), 26.6% (29/109), and 28.4% (31/109), respectively. A significant correlation was observed between ypT(pCR) and ypN0 (P <.001), although discrepancies between the 2 persisted. The combined pathological responses of the primary tumor and lymph nodes were significantly associated with prognosis (P =.040). Patients with signet ring cell carcinoma had a poorer pathological response and significantly worse prognosis (P =.001).

[CONCLUSION] A significant correlation exists between primary tumor and lymph node responses in patients with LAGC treated with neoadjuvant chemoimmunotherapy. The combined assessment of both responses may serve as a reliable predictor of clinical outcomes.