A risk prediction model for metachronous peritoneal metastasis after radical gastrectomy in gastric cancer based on peripheral blood inflammatory markers and tumor pathological features.

PURPOSE: To develop a prognostic scoring system for metachronous peritoneal dissemination (MPM) in gastric cancer patients following radical gastrectomy, based on preoperative peripheral blood inflammatory markers and postoperative tumor histological features. METHODOLOGY: A total of 522 gastric cancer patients who underwent radical gastrectomy were retrospectively analyzed, including 364 patients without MPM and 158 patients with MPM. Peripheral blood samples were collected within 7 days before surgery to measure neutrophil and lymphocyte counts, platelets, C-reactive protein (CRP), carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), and CA125. Four inflammatory indices were calculated: neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), and systemic inflammation response index (SIRI). Histopathological features of the excised tissue were assessed postoperatively. RESULT: Compared with the non-MPM group, patients in the MPM group exhibited significantly larger tumors, a higher prevalence of diffuse-type Lauren patterns, poorly differentiated histology, deeper tumor invasion, more frequent lymph node metastasis, and elevated rates of perineural and lymphovascular infiltration (all P < 0.05). Neutrophil count, platelet count, CRP, NLR, PLR, SII, SIRI, CEA, CA19-9 and CA125 were all increased, whereas lymphocyte counts were reduced in the MPM group (all P < 0.05). Multivariate logistic regression analysis identified tumor size (OR=1.475), depth of invasion (OR=2.602), lymph node metastasis (OR=3.536), NLR (OR=2.457), PLR (OR=1.009), CA19-9 (OR=1.079), and CA125 (OR=1.156) as independent risk factors for MPM. A combined predictive model incorporating these seven parameters demonstrated an area under the receiver operating characteristic curve (AUC) of 0.952. CONCLUSION: A prognostic model integrating preoperative peripheral blood inflammatory indices and postoperative tumor histopathology can accurately predict the risk of metachronous peritoneal metastases in gastric cancer patients after radical gastrectomy.