Combined endocrine effects of LHRH agonist (Zoladex) and tamoxifen (Nolvadex) therapy in premenopausal women with breast cancer.

In premenopausal women with breast cancer, the use of the luteinizing hormone releasing hormone agonist, goserelin, results in the production of serum levels of oestradiol equivalent to those after surgical oöphorectomy or in postmenopausal women. The standard first line hormonal treatment for systemic breast cancer in postmenopausal women is tamoxifen. The combination of goserelin and tamoxifen in premenopausal women has been proposed. We have treated 34 premenopausal breast cancer patients with goserelin (3.6 mg) monthly and tamoxifen (20 mg) twice daily: endocrine data are available on all 34 patients. As with goserelin alone, patients on goserelin and tamoxifen showed transient stimulation of serum follicle stimulating hormone over the first 7-10 days with subsequent low gonadotrophin levels. Serum oestradiol and progesterone levels were reduced to castrate levels in all patients studied; no peaks of serum oestradiol were detected. There is no endocrinological contraindication to the use of goserelin and tamoxifen together in premenopausal women with breast cancer either as adjuvant therapy or in treating advanced disease.