Prognostic value of immune-inflammation index in prostate cancer patients with bone metastases: systematic review and meta-analysis

To evaluate the immune-inflammation index’ prognostic value in prostate cancer bone metastases patients. PubMed, Web of Science, Cochrane and Embase were used to search literature until April 2024. Newcastle–Ottawa Scale was performed to assess study quality. Associations between immune-inflammation index [neutrophil–lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-lymphocyte ratio (MLR), systemic immune-inflammation index (SII)] and overall survival (OS), cancer-specific survival (CSS), or prostate-specific antigen response rate were used to analyze. Review Manager 5.4.1 and Stata 15.1 were conducted for meta-analysis. Evidence for each outcome was evaluated and graded according to GRADE. The systematic search identified 325 related studies, with 7 studies including 2322 patients included for meta-analysis. Patients with higher immune-inflammation index had shorter OS (HR: 1.91; 95% CI 1.44, 2.54; P < 0.00001). Subgroup analysis revealed higher NLR (HR: 1.79; 95% CI 1.00, 3.22; P = 0.05), MLR (HR: 1.88; 95% CI 1.43, 2.45; P < 0.00001), PLR (HR: 1.80; 95% CI 1.38, 2.35; P < 0.0001), and SII (HR: 2.40; 95% CI 1.82, 3.16; P < 0.00001) significantly associated with shorter OS. Additionally, higher NLR associated with shorter CSS (HR: 1.32; 95% CI 1.01, 1.74; P = 0.04). According to GRADE, NLR (OS), MLR (OS), and NLR (CSS) were rated as very low-quality evidence. Very low-quality evidence based on GRADE assessment indicated that high immune-inflammation index, including NLR, PLR, MLR, and SII, were associated with worse prognosis in prostate cancer patients with bone metastases.