Use of 5-alpha reductase inhibitors (5-ARIs) does not appear to have a protective effect on the risk of developing or dying from bladder cancer, according to study findings presented at the American Urological Association 2020 Virtual Experience.

In a prospective cohort study of 39,427 men from the Health Professionals Follow-up Study in the United States, a team led by Keyan Salari, MD, PhD, a urologic oncologist at Massachusetts General Hospital and Harvard Medical School in Boston found no significant difference between prediagnostic 5-ARI use and development or death from bladder cancer after adjusting age, smoking, alcohol use, and other potential confounders. In contrast with prior retrospective studies, the investigators observed a non-significant 25% and 54% increased risk bladder risk and death associated with 5-ARI use, possibly due to increased likelihood of urologic evaluation among men on these medications.

Duration of 5-ARI also was not associated with bladder cancer risk or death.

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During 16 years and 595,377 person-years of follow-up, 943 men were diagnosed with bladder cancer and 159 died from it. Of the entire cohort, 4105 (10.4%) reported ever using 5-ARIs during the study period.

The 5-ARIs are a well-tolerated class of medications commonly prescribed to reduce the size of the prostate, but recent retrospective studies have suggested they might also have a beneficial effect on bladder cancer development and/or recurrence, Dr Salari said.

 “A strategy for chemoprevention of bladder cancer would have tremendous clinical implications for how this highly morbid disease is treated and possibly prevented all together,” Dr Salari told Renal & Urology News. “However, we found that 5-alpha reductase use had no beneficial effect on the risk of developing or dying from bladder cancer in a large prospective cohort study of men from the Health Professionals Follow-Up Study. Our study shows no evidence that 5-alpha reductase inhibitors are an effective chemopreventative agent against bladder cancer.”


Caldwell, Giovannuci E, Schernhammer E, et al. 5-ɑ reductase inhibitors and risk of overall and fatal bladder cancer. Presented at the American Urological Association 2020 Virtual Experience held in May. Abstract PD50-10.