Presentation Authors: Pedro Glusman Knijnik*, Pietro Waltrick Brum, Eduardo Tosetto Cachoeira, Arthur de Oliveira Paludo, Antonio Rebello Horta Gorgen, Lucas Medeiros Burttet, Jeruza Lavanholi Neyeloff, Brasil Silva Neto, Porto Alegre, Brazil
Introduction: Prostate cancer (PC) prevention is very desirable due to its high incidence and impact on healthcare. 5-alpha reductase inhibitors (5ARI) can potentially reduce the risk of PC. A 2010 meta-analysis demonstrated that 5ARI reduced the risks of diagnosis of PC, but could not assess the effect on specific or overall survival. We aimed to update this meta-analysis and most importantly to include data from observational studies on the analysis. Our main objective was to evaluate the impact of 5ARI for PC prevention on specific and overall survival.
Methods: We searched MEDLINE, EMBASE, Cochrane, ClinicalTrials and BVS through April 2018 to identify RCT and observational studies. We included articles with mortality or prostate cancer incidence for men using 5ARI previous to the cancer diagnosis. Each article was assessed independently by two reviewers, both for study selection and data extraction. Summary effects were calculated using Mantel-Haenszel method in a random effects model, and heterogeneity was assessed using IÂ² statistics.
Results: 3432 articles were retrieved from the above databases (after exclusion of duplicates). 179 articles were selected for full review, 20 had adequate data for analysis (11 RCT and 9 cohorts). Use of 5ARI had no impact on overall and cancer-specific survival, nor on high-grade prostate cancer diagnosis (attached plots). We identified a reduction in overall cancer diagnosis (16 studies, RR 0.82 95% CI 0.69 - 0.96, I2 94%). The incidence of low-grade PC diagnosis was not statistically significant (8 studies, RR 0.81 95%CI 0.62 - 1.06, I2 95%) on the main analysis, but a subgroup considering only RCT identified a substantial reduction in low-grade PC diagnosis (3 studies, RR 0.65 95% CI 0.54-0.79).
Conclusions: Despite concerns cited by previous studies, we identified no effect on mortality or incidence of high-grade cancers. By reducing overall prostate cancer diagnosis, the use of 5ARI may have an impact on the reduction of PC overdiagnosis and overtreatment.