Prediction of Peritoneal Cancer Index and Prognosis in Peritoneal Metastasis of Gastric Cancer Using NLR-PLR-DDI Score: A Retrospective Study

OBJECTIVE: The peritoneal cancer index (PCI) is used to evaluate the peritoneal metastasis of gastric cancer. A higher value indicates more widespread and/or larger tumors in the peritoneal cavity. The neutrophil–lymphocyte ratio (NLR) and platelet–lymphocyte ratio (PLR) are representative blood markers of systemic inflammatory responses, and D-dimer (DDI) is the final stable product of fibrin. This study explores the association of NLR, PLR, and DDI with PCI and assesses the clinical utility of a new blood score combining the NLR, PLR, and DDI (NPD score) for PCI and the prognosis prediction of gastric cancer. METHODS: This was a single-center, nonrandomized, retrospective, cohort study. We evaluated the risk factors for high PCI (≥15) using univariate and multivariate analyses. According to the findings of the ROC analysis, we determined the cut-off values of NLR, PLR and DDI and created the NPD score. The patients were grouped into high-risk and low-risk groups based on their NPD score (<2 and ≥2, respectively). RESULTS: Univariate and multivariate analysis demonstrated that the NLR, PLR, and DDI were independent risk factors for high PCI (P < 0.05). The NPD score of the high-risk group was ≥2, and the NPD score of the low-risk group was <2. The median survival time was 14.2 in the high-risk group and 25.6 in the low-risk group. The NPD score was significantly higher in the high-PCI group than that in the low-PCI group. The survival of the high-risk group was significantly worse than that of the low-risk group (P = 0.003). NPD score decrease was an independent predictive factor for PCI decrease. CONCLUSION: NLR, PLR, and DDI are potential independent risk factors for high PCI in patients with peritoneal metastasis of gastric cancer. The NPD scoring system can help in predicting PCI and the prognosis of patients with peritoneal metastasis of gastric cancer.