The Effect of Statins on the Incidence and Prognosis of Bladder Cancer: A Systematic Review and Meta-Analysis

Background: Statins are widely used due to their ability to lower plasma cholesterol and offer protection from the effects of atherosclerosis. However, their role in urology and specifically bladder cancer remains unclear. We aimed to systematically address this issue in the literature and determine any possible effects of statin therapy on bladder cancer. Methods: We searched MEDLINE (PubMed) and Cochrane Library databases for records up to 26 March 2023, for studies evaluating the effects of statins on urinary bladder cancer (UBC). We included all randomized controlled trials (RCTs), cohorts, and case-control studies that were conducted on the adult population. PROSPERO registration number: CRD42023407795. Results: Database searches returned 2251 reports, and after thorough investigation and assessment for eligibility, 32 reports were included in the analysis. Of them, 4 were RCTs, 6 were case-control studies, and 22 were cohort studies. Our qualitative analysis demonstrated no association between statin administration and UBC local control, recurrence, survival, or mortality, or between statin administration and bacille Calmette-Guerin (BCG) immunotherapy effectiveness. A meta-analysis of 10 trials revealed a non-significant reduction of 11% in UBC risk among users compared with non-users in RCTs (RR: 0.89, 95% CI 0.68-1.16, p = 0.37) and a non-significant increase of 32% of UBC risk among statin users compared with non-users in the analysis of the cohort studies (RR: 1.32, 95% CI 0.76-2.30, p = 0.33). Conclusions: Our results provide strong evidence to support the neutral effect of statins on UBC local control, recurrence, survival, and mortality, and on BCG immunotherapy. Our meta-analysis revealed a non-significant effect on UBC risk among statin users when compared with non-users, indicating no statin effect on UBC incidence and overall prognosis.