Systematic Review and Meta-analysis of the Efficacy and Tolerability of Immune Checkpoint Inhibitors in the Treatment of Prostate Cancer

Context: One of the most common cancers in men is prostate cancer, which can lead to death. Immune checkpoint inhibitors (ICIs) are drugs that have been proposed in recent years as proposed treatments for prostate cancer. Objectives: The aim of this study was to review the efficacy and tolerability of ICIs in these patients. Data Sources: From January 1, 1990, to January 1, 2022, using the keywords in checkpoint inhibitors, prostate cancer, efficacy, and tolerability, systematically reviewed databases such as PubMed, ClinicalTrial.gov, Web of Science, Scopus, Cochrane Library, ScienceDirect and Google Scholar based on the protocol registered in Prospero were identified as CRD42021252562. Results: Out of 690 studies found, 43 studies were reviewed for evaluation in terms of inclusion criteria, and finally 6 studies were included in the design. In the analysis of selected studies, 1 800 patients were studied, and the range of sample size was from 23 to 799. According to the results of the meta-analysis, there was no significant difference in death risk compared to ICI + radiotherapy with radiotherapy + placebo (HR: 0.96, 95% CI: 0.74, 1.23, P = 0.74). Combined results from 2 clinical trials demonstrated that the risk of death in the radiotherapy + ICI group was less than in the group just treated with radiotherapy (HR: 0.69, 95% CI: 0.61, 0.77, (P < 0.001), 0.77, P < 0.001). To evaluate tolerability, the results showed a non-significant difference between the groups considering the overall prevalence of treatment-related side effects (RR: 1.59, 95% CI: 0.75, 3.39, I2 = 98%). Conclusions: The present meta-analysis showed that the use of safety checkpoint inhibitors has been associated with improved survival without progression, but their effect on increasing overall survival has not been confirmed.