[Are all LH-RH analogues equally effective in prostate cancer?].

BACKGROUND: Gonadotropin analogues are used in patients with prostate cancer for Leydig cell suppression with serum testosterone levels within the range after castration. Insufficient effect may have adverse consequences on the clinical course. MATERIAL: At the Norwegian Radium Hospital, serum testosterone is routinely analysed in patients who use gonadotropin analogues and are referred to the hospital for treatment of hormone-resistant prostate cancer. RESULTS/COMMENTS: Analyses of serum testosterone in two patients with advanced prostate cancer revealed insufficient androgen suppression in spite of continuous treatment with leuprorelin 11.25 mg. After substitution of leuprorelin by goserelin, serum testosterone decreased to levels compatible with those after surgical castration. In patients with advanced prostate cancer who use leuprorelin, monitoring of serum testosterone is necessary, with onset no later than 12 weeks after start of treatment. The diagnosis of "hormone resistant prostate cancer" requires that the patient's serum testosterone is measured within the range corresponding to surgical castration.