Therapy with gonadotropin releasing hormone agonists (zoladex) in premenopausal females with metastastic breast cancer

Abstract

Medicinal castration using GnRH-analogues is a new therapeutic possibility for treating metastasizing breast cancer in premenopausal women. A total of 22 premenopausal patients were included in the study reported here, all of them low-risk cases. Twenty of the 22 patients had hormone receptor-positive primary tumors. A slow-release depot form of Zoladex (ICI 118630) was used as a GnRH agonist and was administered subcutaneously (3.6 mg) at four-week intervals. The long-term administration of Zoladex brought about a significant reduction in blood FSH, estradiol, and progesterone levels within one to four weeks. In contrast, there were no detectable changes in ACTH, DHEAS, cortisol, testosterone, prolactin, or androstendion levels. Therapy-induced amenorrhea occurred in all cases. The objective remission rate achieved (complete and partial remission) was 45%. As opposed to other formulations, the use of Zoladex as a GnRH analog in depot form has significant advantages, which become particularly evident through improved compliance. With Zoladex therapy an effective drug-induced castration can be accomplished in premenopausal women. As regards its efficacy it is comparable to an ovarectomy, though with less pronounced side effects.