We report the case of a T3 prostate cancer in a 70-year-old white man. Hormone therapy represents a prominent branch in the treatment of locally advanced and metastatic prostate cancer. Gonadotropin-releasing hormone agonists have been proven to have a double effect on androgen metabolism: an initially stimulating, followed by an inhibitory, effect on the pituitary gland. This phenomenon may be noxious in the case of gonadotroph adenoma, with subsequent symptoms of intracranial hypertension. Gonadotropin-releasing hormone antagonists (abarelix), by avoiding the flare-up reaction, might be used in such instances.