Prognostic significance of pretreatment systemic immune-inflammation index in patients with prostate cancer: a meta-analysis

BACKGROUND: The SII (systemic immune-inflammation index) has been extensively reported to have a prognostic value in prostate cancer (PCa), despite the unconformable results. The purpose of this meta-analysis is to quantify the effect of pretreatment SII on survival outcomes in patients with PCa. METHODS: The following databases were searched: Web of Science, Cochrane Library, PubMed, Embase, and China National Knowledge Infrastructure (CNKI). For exploration of the SII’s correlations with the overall survival (OS) and the progression-free survival/biochemical recurrence-free survival (PFS/bRFS) in PCa, the pooled hazard ratios (HRs) were assessed within 95% confidence intervals (CIs). RESULTS: The present meta-analysis covered 10 studies with 8133 patients. Among the PCa population, a high SII was linked significantly to poor OS (HR = 2.63, 95% CI = 1.87–3.70, p < 0.001), and worse PFS/bRFS (HR = 2.49, 95% CI = 1.30–4.77, p = 0.006). However, a high SII was not linked significantly to T stage (OR = 1.69, 95% CI = 0.86–3.33, p = 0.128), the metastasis to lymph node (OR = 1.69, 95% CI = 0.69–4.16, p = 0.251), age (OR = 1.41, 95% CI = 0.88–2.23, p = 0.150), or the Gleason score (OR = 1.32, 95% CI = 0.88–1.96, p = 0.178). CONCLUSIONS: For the PCa sufferers, the SII might be a promising prognostic biomarker, which is applicable to the high-risk subgroup identification, and provide personalized therapeutic strategies. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12957-022-02878-7.