Systemic immunoinflammatory index and prognostic nutrition index for predicting pathologic responses of patients with advanced gastric cancer after neoadjuvant therapy for advanced gastric cancer.

To investigate the value of prognostic nutrition index (PNI) and systemic immunoinflammatory index (SII) for predicting pathological responses of patients with advanced gastric cancer (GC) after neo-adjuvant chemotherapy (NACT). The clinicopathological data of 326 patients with advanced GC who received NACT in Xiangya School of Medicine, Central South University (The First People's Hospital of Changde City) from January 2017 to December 2021 were retrospectively collected. The SII and PNI of patients were calculated. The receiver operating characteristics (ROC) curve was leveraged for getting the optimal cutoff values of SII and PNI. The pathological response of patients after NACT, as obtained from their postoperative pathological examinations, was evaluated based on the tumor regression grade (TRG) criteria. Multivariate regression analysis was employed for identifying factors that led to various pathological responses after NACT in advanced GC patients. The log-rank test was utilized for between-group comparison of patients' survival curves. The SII and PNI were 507.45 and 48.48 respectively, and their levels were divided into high and low groups. Pathological response (TRG 0-1) was observed in 66 cases (20.25%), while non-pathological response (TRG 2-3) was observed in 260 cases (79.75%). The results of multivariate logistic regression analysis showed that tumor diameter < 5 cm, ypT T0-T2, ypN N0, chemotherapy regimen XELOX (capecitabine combined with oxaliplatin), SII < 507.45 (P=0.002), PNI > 48.48 were all independent factors affecting the pathological responses of advanced GC patients after NACT (all P < 0.05). With SII and PNI being included, the AUC was 0.821 (95% CI: 0.765-0.876), and the specificity was 87.90% and the sensitivity was 64.20%. The Kaplan-Meier survival curve analysis showed that NACT patients with tumor diameter < 5 cm, ypT T0-T2, ypN N0, XELOX chemotherapy regimen, SII < 507.45 and SII ≥ 507.45 had a higher survival rate. (P < 0.001). Before treatment, tumor diameter < 5 cm, ypT T0-T2, ypN N0, chemotherapy regimen XELOX, SII < 507.45, PNI > 48.48 were all independent factors affecting the pathological response of advanced GC patients after NACT. Moreover, the inclusion of SII and PNI increased the accuracy of predicting the pathological response of patients after NACT.