Preoperative Systemic Immune-Inflammation Index (SII) for Predicting the Survival of Patients with Stage I-III Gastric Cancer with a Signet-Ring Cell (SRC) Component

BACKGROUND: Recently, a novel systemic immune-inflammation index (SII) based on peripheral lymphocytes, neutrophils, and platelets has been reported to be correlated with patient prognosis in several malignancies, including gastric cancer. However, the prognostic value of the SII for gastric cancer patients with a signet-ring cell (SRC) component has not yet been reported. In this study, we aimed to assess the prognostic value of the SII in gastric cancer patients with an SRC component after curative resection. METHODS: This study was a retrospective analysis of 512 GC patients with an SRC component who underwent curative resection. The prognostic value of the SII was analyzed by the Kaplan-Meier method and Cox proportional hazards regression model. RESULTS: In our study cohort, an optimal cut-off value for the SII of 527 was used to stratify patients with gastric cancer (GC) into low (<527) and high SII (≥527) groups. Our study indicated that a high SII (≥527) was significantly correlated with a large tumor size (p < 0.001), infiltration of serosa (p < 0.001), lymph node metastasis (p < 0.001), and advanced TNM stage (p < 0.001). Univariate and multivariate analyses further demonstrated that a low SII was correlated with better clinical outcome and was an independent prognostic predictor in GC patients with an SRC component. Furthermore, the SII retained prognostic value in the subgroup analysis, including subgroup of different TNM stages and pure or mixed signet-ring cell carcinomas (SRCCs). CONCLUSION: The SII is a simple, promising, and practical prognostic biomarker for patients with surgically resected mixed SRCC and pure SRCC. The SII could complement current prognostic tools for better treatment planning and stratification of patients.