(AC) 5-Alpha Reductase Inhibitor Use and Risk of Kidney and Bladder Cancer in Men with Benign Prostatic Hyperplasia: A Population-Based Cohort Study

Friday, August 26, 2022

8:00 AM – 6:00 PM CEST

Location: Hall E South

Publication Number: 319

Presenting Author(s)

Niamh Doherty
– Queen's University of Belfast (Centre for Public Health), Queens University Belfast, Belfast, Belfast, United Kingdom

Co-Author(s)

Christopher Cardwell, PhD
– Professor, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom
Peter Murchie
– Professor, University of Aberdeen, Aberdeen, Scotland, United Kingdom
Christopher Hill
– Belfast City Hospital, Belfast, UK, United Kingdom
Laurent Azoulay, PhD
– Associate Professor, McGill University, Montreal, Quebec, Canada, QC, Canada
Blánaid Hicks
– Lecturer, Queen’s University Belfast, Belfast, Northern Ireland, United Kingdom

Background: 5-alpha reductase inhibitors (5ARi) are commonly used in the treatment of men with benign prostatic hyperplasia (BPH). Pre-clinical evidence suggests that 5-alpha reductase inhibitors are associated with reduced incidence of some urological cancers however epidemiological studies to date have been conflicting.

Objectives: This study aimed to investigate the risk of bladder and kidney cancers with the use of 5ARi’s compared to alpha blockers in men with BPH.

Methods: We conducted a retrospective cohort study in the UK Clinical Practice Research Datalink using an active comparator new user design. From a base cohort of patients with incident BPH, we identified new users of 5ARi’s and alpha blockers following a BPH diagnosis. A 1-year lag period was applied therefore patients were followed up from one year after their first prescription until a first ever diagnosis of kidney or bladder cancer, death from any cause, end of registration with the general practice or 31st of December 2017. Cox proportional hazards models were used to calculate hazard ratios (HR) and 95% confidence intervals (CIs) of incident kidney and bladder cancer associated with the use of 5ARi compared with alpha blockers, using an intention-to-treat approach. The primary analysis was repeated censoring on switching or adding-on of the two study drugs. Additional sensitivity analyses were performed to assess robustness of findings including varying time lag and propensity score weighting.

Results: 5,414 5ARi new users and 37,681 alpha blocker new users were identified for this study with an average follow-up of 6.63 years. Overall, the use of 5ARi’s was not associated with the risk of kidney or bladder cancer (HR: 1.26 95%CI 0.74-2.12 and HR: 0.89 95%CI 0.64-1.23, respectively). Analyses censoring on switching or add on of study drugs also showed no association. Findings from sensitivity analysis varying lag period and using standard mortality ratio weights were also consistent.

Conclusions: We found no association between the use of 5ARi’s and kidney or bladder cancer incidence in men with benign prostatic hyperplasia compared to alpha blockers. Due to a low number of observed kidney cancer cases further studies are warranted to confirm findings.