Endocrine effects of combination antioestrogen and LH-RH agonist therapy in premenopausal patients with advanced breast cancer.

Thirty-eight premenopausal breast cancer patients were treated for periods up to 12 months with a sustained-release formulation of the luteinizing hormone-releasing hormone agonist goserelin [Zoladex, (D-Ser(But)6Azgly10-LH-RH); 3.6 mg depot every 4 weeks] either alone or in combination with the antioestrogen tamoxifen citrate (Nolvadex 40 mg/day). In both treatment groups serum gonadotrophin concentrations fell durig the first month of therapy and were suppressed on continued treatment. In patients treated with the combination therapy FSH concentrations were significantly reduced in comparison with goserelin alone. Relatively normal ovarian activity was observed during the first few weeks of therapy. Thereafter, oestradiol and progesterone concentrations rapidly declined in both treatment groups. Slightly lower serum oestradiol concentrations were recorded in patients receiving combination therapy. No significant adverse side-effects were recorded in either group of patients.