Long-term use of 5α-reductase inhibitors and the risk of male breast cancer

Background The 5α-reductase inhibitors (5-ARI) finasteride and dutasteride are indicated for the treatment of lower urinary tract symptoms caused by benign prostatic hyperplasia. Case reports have suggested that 5-ARIs increase the risk for male breast cancer, with no conclusive evidence. The objective of this study was to quantify the association between use of 5-ARIs and the risk for male breast...