From May 1987 to May 1989 sixty one pre- and perimenopausal women with advanced or recurrent breast cancer entered in an open non comparative study. They were treated, as a first-line therapy, with goserelin (Zoladex ICI-118630) a long acting gonadotropin-releasing hormone (LH-RH)-analogue in a depot formulation. Fifty three patients were evaluable for response; median age at entry was 41 years (range 28-56). Serum concentrations of 17 beta estradiol, LH and FSH were significantly suppressed within the first four weeks of therapy and remained suppressed for the whole duration of treatment. Subjective responses were observed, such as pain reduction and/or performance status improvement in 58% of patients. Overall objective response (CR + PR) occurred in 16 (30.2%) patients in all major sites of disease with a median time to response of 12 weeks (range 8 to 48 weeks) and a lifetable median duration of response of 36 weeks (range 16 to 76 weeks). The lifetable median time to progression was 17 weeks (range 5 to 76 weeks). Goserelin depot was well tolerated with no withdrawal due to possible adverse reactions. The observed subjective and objective response rates are comparable to those induced by surgical oophorectomy. Goserelin provides a well tolerated medical alternative to ovarian ablation, without the morbidity associated to surgery. In conclusion the present paper suggests that this innovative chemical estrogen deprivation, in premenopausal breast cancer patients, might be favorably investigated as an adjuvant therapy in future clinical trials.