Failure of a gonadotropin-releasing hormone analogue to lower serum testosterone in patients with prostate cancer

Abstract We report 3 patients with prostate cancer who showed an unexplained failure to lower their serum testosterone levels despite monthly treatment with gonadotropin-releasing hormone analogues. We recommend assessing the serum testosterone levels when gonadotropin-releasing hormone analogue treatment is ineffective, before the diagnosis of hormone-refractory cancer is established.