333 pre- and peri-menopausal patients with breast cancer entered a programme of open studies on the effect of goserelin. Of the 333 patients, 265 patients were entered into assessable efficacy studies. Efficacy data were analysed from 228 eligible patients receiving 3.6 mg of goserelin administered as a subcutaneous injection of a depot formulation once every 28 days. Mean serum luteinising hormone (LH) and oestradiol concentrations were suppressed by day 22 after the first injection. Subjective response occurred in 68.3% of patients assessed. Objective response (UICC criteria) occurred in 36.4% of patients and the lifetable median duration of response was 44 weeks. Responses were observed in all histological grades of tumour, and regardless of oestrogen receptor status. Treatment was well tolerated with no withdrawals due to possible adverse reactions of which hot flushes (75.9%) and loss of libido (47.4%) were commonly encountered. Goserelin provides an effective well tolerated medical alternative to ovarian ablation in the management of advanced breast cancer.