Five-alpha reductase inhibitor use and risk of colorectal cancer in men with benign prostatic hyperplasia: a population-based cohort study

Niamh Doherty, Christopher Cardwell, Peter Murchie, Christopher Hill, Laurent Azoulay , Blánaid Hicks

Research output: Contribution to journalMeeting abstractpeer-review

Abstract

Background: Five-alpha reductase inhibitors (5ARi) are commonly pre-scribed for the treatment of benign prostatic hyperplasia (BPH) in men. Pre-clinical evidence suggests that 5ARi's may have a protective role in colorectal cancer initiation. However, no studies to date have investigated this association at the population level.

Objectives: This study aimed to investigate the risk of colorectal cancer associated with the use of 5ARi in a UK population.

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. After a 1-year exposure lag patients were followed up until a first ever diagnosis of colorectal cancer, death from any cause, end of registration with the general practice or 31 of December 2017. Cox proportional hazards models were used to calculate hazard ratios(HR) and 95% confidence intervals (CI) of incident colorectal cancer associated with the use of 5ARi compared with alpha-blockers, using an intention-to-treat approach. We repeated the primary analysis censoring on switch or add-on of the study drug and using inverse probability of treatment weights. Additional sensitivity analyzes were performed to assess robustness of findings including varying time lag and using multiple imputation to account for missing data.

Results: 5018 5ARi new users and 34 925 alpha-blockers new users were identified for this study with an average follow-up of 6.61 years. Overall, the use of 5-alpha reductase inhibitors was not associated with the risk of colorectal cancer (HR: 1.11 95% CIs 0.88–1.40). Analysis censoring on switching or adding on of study drugs and using inverse probability of treatment weights found similar results (HR:1.09 95% CIs 0.81–1.45 and HR: 1.11 95% CIs 0.88–1.41, respectively). Findings from sensitivity analysis varying lag period and using multiple imputation were also consistent.

Conclusions: This was the first epidemiological investigation of 5ARisand colorectal cancer. Overall, in this study, the use of 5ARi's in men with BPH was not associated with a reduced risk of colorectal cancer compared to men using alpha blockers.

Original languageEnglish
Article number163
Pages (from-to)67
Number of pages1
JournalPharmacoepidemiology and Drug Safety
Volume31
Issue numberS2
Publication statusPublished - 23 Sept 2022
Event38th International Conference on Pharmacoepidemiology and Therapeutic Risk Management 2022 - Copenhagen, Denmark
Duration: 26 Aug 202228 Aug 2022

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