Inclusion Criteria

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed metastatic breast
cancer that has failed prior tamoxifen therapy Measurable disease No CNS metastases
Hormone receptor status: Estrogen or progesterone receptor positive At least 10 fmol/L by
biochemical assay OR At least 10% of cells positive by immunochemistry

PATIENT CHARACTERISTICS: Age: 18 and over Sex: Female Menopausal status: Premenopausal
defined as estradiol at least 30 pg/mL, follicle stimulating hormone less than 25 mIU/mL,
and luteinizing hormone less than 15 mIU/mL Performance status: ECOG 0-2 Life expectancy:
Not specified Hematopoietic: Absolute neutrophil count at least 1,000/mm3 Platelet count
at least 50,000/mm3 Hepatic: Bilirubin no greater than 2.0 mg/dL AST no greater than 3
times normal Renal: Stable renal function Pulmonary: No pulmonary embolism Other: Not
pregnant or nursing Negative pregnancy test Fertile patients must use effective
non-hormonal contraception during and for 12 weeks after study No other prior malignancy
except nonmelanoma skin cancer or carcinoma in situ of the cervix No known
hypersensitivity to luteinizing hormone releasing hormone (LHRH), LHRH agonist analogues,
or any of the components of goserelin

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No more than 2
prior chemotherapy regimens Endocrine therapy: See Disease Characteristics No prior
hormonal therapy for metastatic breast cancer No concurrent estrogen (hormone replacement)
therapy No other concurrent hormonal agents for breast cancer (e.g., tamoxifen,
anastrozole, letrozole, aminoglutethimide, or megestrol) No concurrent corticosteroids for
breast cancer unless already receiving such therapy at study entry Radiotherapy: Not
specified Surgery: Not specified Other: Concurrent bisphosphonates allowed for bone
disease provided measurable disease in non-osseous sites No concurrent anticoagulant
therapy