Purpose: This study aimed to investigate the effect of androgen suppression therapy (AST), comprising a 5-α reductase inhibitor (5-ARi) and androgen deprivation therapy (ADT), on the risk of bladder cancer incidence, recurrence, and mortality.
Materials and methods: We used the PRISMA statement to report the methods and results of this meta-analysis. Bladder cancer incidence, recurrence, and mortality after 5-ARi treatment and ADT were assessed using risk ratios (RRs) and hazard ratios (HRs) with 95% confidence intervals (CIs). The protocol of this study is registered in the PROSPERO database (No. CRD42018118627).
Results: We analyzed nine studies (n = 377,427) assessing the secondary effect of AST, with a mean follow-up period of 6 years (range, 2-13 years). Our result showed that the incidence of bladder cancer was significantly reduced when 5-ARi treatment (RR, 0.69; 95% CI, 0.58-0.81; I2 =0%) and ADT (HR, 0.81; 95% CI, 0.70-0.94; I2 =33%) were initiated before diagnosing bladder cancer. When treatment was initiated after diagnosing bladder cancer, 5-ARi treatment reduced cancer-specific mortality (RR, 0.29; 95% CI, 0.20-0.42; I2 =4.1%), whereas ADT reduced bladder cancer recurrence (HR, 0.30; 95% CI, 0.19-0.49; I2 =0%).
Conclusions: This study corroborates that the use of 5-ARi and ADT could be helpful in managing bladder cancer and should not be limited to prostatic abnormalities.
Keywords: 5-α reductase inhibitor; Bladder cancer; androgen deprivation therapy; androgen suppression therapy.