Systemic immune inflammation index and gastric cancer prognosis: A systematic review and meta‑analysis
Xiaomao Yang, Chen Wu
Abstract
The present study aimed to pool the available data on the associations between the systemic immune inflammation index (SII) and overall survival (OS) or recurrence‑free survival (RFS) in patients with gastric cancer (GC). A systematic search was conducted in the PubMed, EMBASE and Scopus databases for observational studies, and a random effects model was used to conduct the statistical analysis. Pooled effect sizes were reported as hazard ratios (HRs) with corresponding 95% confidence intervals (CI). Data from 30 studies (24 conducted in China) with follow‑ups ranging between 15.5 and 65.6 months were analyzed. Patients with GC and high SII levels had poor OS (HR, 1.53; 95% CI, 1.34‑1.75) and recurrence free survival (HR, 1.41; 95% CI, 1.17‑1.70). These increased risks were present irrespective of the treatment strategy (surgical or non‑surgical management), the sample size (<500 and ≥500) and the cut‑off used to define high and low SII (<600 and ≥600 x10<sup>9</sup> cells/l). The results of this meta‑analysis suggest that high pretreatment SII levels were associated with poor OS and RFS in patients with GC.