The Systemic Immune-inflammation Index Is an Independent Prognostic Factor for Gastric Cancer Patients Who Receive Curative Treatment.

Abstract

Systemic immune-inflammation index (SII) was developed and evaluated for various malignancies. This study evaluated the clinical impact of the SII in patients with gastric cancer (GC) who received curative treatment. Patients who underwent curative resection for GC at Yokohama City University between 2005 and 2020 were chosen consecutively based on their medical records. SII was calculated as follows: platelet (cell/mm3 ×103)× neutrophil (cell/mm3)/lymphocyte (cell/mm3). Three measurements were obtained preoperatively. In total, 258 patients were enrolled in this study. Based on the 3- and 5-year survival rates and previous studies, we set the cutoff value of the SII to 550. The 258 patients were classified into the SII-low (n=152) and SII-high (n=106) groups, respectively. The 3- and 5-year overall survival (OS) rates were 82.6% and 78.7%, respectively, in the SII-low group and 74.5% and 61.9%, respectively, in the SII-high group. There were significant differences between the two groups (p<0.001). In the multivariate analysis of factors associated with OS, the SII was identified as an independent prognostic factor (hazard ratio=1.816; 95% confidence interval=1.075-3.069, p=0.026). Similar results were observed for recurrence-free survival. In addition, the incidence of postoperative surgical complications was 30.9% in the SII-low group and 45.2% in the SII-high group (p=0.019). The SII was an independent prognostic factor for GC. Thus, the SII may be a promising biomarker for the treatment and management of GC.