In a recent study of 183,842 men with locoregional prostate cancer, 48.4% of whom received a gonadotropin-releasing hormone (GnRH) agonist and 2.2% of whom underwent bilateral orchiectomy, treatment with a GnRH agonist was associated with a significantly higher incidence of biliary disease compared with no treatment (15.7 cases vs 13.4 cases per 1,000 person-years). Androgen deprivation by orchiectomy, on the other hand, had no effect on risk of biliary disease.