Effect of Immune Checkpoint Inhibitors on Advanced Prostate Cancer: A Meta-Analysis

This meta-analysis evaluates the effect of immune checkpoint inhibitors (ICIs) on advanced prostate cancer, assessing efficacy and safety profiles compared with non-ICI regimens.

We searched PubMed, Web of Science, Embase and Cochrane Library for pertinent studies, including randomised controlled trials and nonrandomised controlled trials on immunotherapy for prostate cancer. R software was employed for meta-analysis to assess hazard ratios (HRs) for median survival, overall survival (OS), objective response rate (ORR) and serum prostate-specific antigen (PSA) response rate. Egger test, funnel plot analysis and sensitivity analysis were performed to evaluate the results. Heterogeneity sources were explored via meta-regression.

Our study included 19 studies with 3661 participants. Findings indicated no significant improvement in OS (HR = 1.04, 95% confidence interval (CI) = 0.9-1.18), progression-free survival (HR = 0.95, 95% CI = 0.83-1.09) or response rates (PSA = 0.12, 95% CI = 0.08-0.18; ORR = 0.12, 95% CI = 0.08-0.18), with substantial variation in outcomes (I² ≥60%). The rates of adverse events (AEs) varied, with notable incidences of Grade ≥3 reactions. The incidence rates for immune-related AEs were Grade ≥3 AEs, and all-grade AEs 0.37 (95% CI = 0.12-0.72, I² = 96%, p < 0.01), 0.90 (95% CI = 0.83-0.94, I² = 92%, p < 0.01) and 0.38 (95% CI = 0.28-0.49, I² = 94%, p < 0.01). In the meta-regression analysis of confounding factors, only therapy was determined to be significant in PSA response rate.

ICI therapy exhibits potential efficacy in some patients with prostate cancer. However, its widespread application is limited by its uncertain efficacy and potential adverse reactions. Future research should focus on optimising patient selection through biomarkers and improving ICI treatment strategies to enhance efficacy and safety.