Using 5α-reductase inhibitors (5-ARIs) to treat patients with lower urinary tract symptoms is not associated with an increased risk of prostate cancer (PCa), according to a study published in the Journal of the National Cancer Institute.1

A previous study showed that using 5-ARIs (eg, finasteride and dutasteride) to treat benign prostate hyperplasia decreased the risk of low-grade PCa, though data regarding high-grade PCa are conflicting.

For this population-based prospective study, researchers accessed the Stockholm PSA [prostate-specific antigen] and Biopsy Register to analyze data from 333,820 men who underwent PSA testing between 2007 and 2015. Eligible patients did not have any history of PCa and were not previously exposed to 5-ARIs.

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In the cohort, 23,442 were exposed to 5-ARIs at some point during the study period: 32.1% took 5-ARIs for 0.1 to 2 years, 26.1% for 2 to 4 years, 28% for 4 to 6 years, and 13.8% for 6 to 8 years.

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An analysis that excluded PSA levels suggested that 5-ARIs do not decrease the risk for PCa among patients treated with 5-ARIs for 0.1 to 2 years (hazard ratio [HR], 1.00; 95% CI, 0.88-1.15, P=.92). Further analysis showed, however, that 5-ARI use was associated with a decreased risk of overall PCa from 2 years of exposure through the end of the study (2-4 years: HR, 0.49; 95% CI, 0.41-0.60; P<.001; 4-6 years: HR, 0.53; 95% CI, 0.41-0.69, P<.001; 6-8 years: HR, 0.42; 95% CI, 0.22-0.81; P=.01).

After accounting for PSA levels, furthermore, 5-ARI use was significantly associated with a reduced risk of PCa regardless of exposure duration.

Reduction of risk was observed for cancers with Gleason Scores of 6 to 7, but not for cancers with a Gleason Score of 8 to 10.

The authors concluded that “overall, together with the benefits of symptom relief and a decreased risk of surgical procedures, treatment with 5-ARI for lower urinary tract symptoms seems beneficial and safe with respect to prostate cancer risk.”


  1. Wallerstedt A, Strom P, Gronberg H, Nordstrom T, Eklund M. Risk of prostate cancer in men treated with 5α-reductase inhibitors—a large population-based prospective study. J Natl Cancer Inst. 2018 Mar 14. doi: 10.1093/jnci/djy036 [Epub ahead of print]

This article originally appeared on Cancer Therapy Advisor