Role of 5α-reductase inhibitors in prostate cancer prevention and treatment.

Although testosterone is the most abundant serum androgen, dihydrotestosterone is the main prostatic androgen. Testosterone is converted to dihydrotestosterone by the enzyme 5α-reductase (5α-R). Dihydrotestosterone plays an important role in several human diseases, including benign prostate enlargement and prostate cancer. The observation that males born with 5α-R 2 deficiency have never been reported to develop prostate cancer stimulated interest in development of 5α-R inhibitors. Thus far, 2 5α-R inhibitors are approved for clinical use. Several trials evaluated the use of 5α-R inhibitors in prostate cancer prevention and treatment and will be reviewed in this article.