Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed breast cancer meeting 1 of the following criteria:

- Metastatic disease (M1)

- Multiple sites of new disease that is clinically obvious metastatic disease
(e.g., multiple sites of new osseous disease)

- Measurable or nonmeasurable disease

- No known brain or CNS metastases

- Hormone receptor status:

- Estrogen-receptor positive* AND/OR

- Progesterone-receptor positive* NOTE: *Positivity defined as estrogen binding of
> 10 fmol/mg cytosol protein by ligand binding assay or positive by
immunohistochemistry

PATIENT CHARACTERISTICS:

Age

- Not specified

Sex

- Female

Menopausal status

- Postmenopausal, as defined by 1 of the following:

- Prior bilateral oophorectomy

- More than 12 months since last menstrual period with no prior hysterectomy

- At least 55 years of age with prior hysterectomy

- Under 55 years of age with a prior hysterectomy without oophorectomy and with
estradiol and follicle-stimulating hormone levels consistent with menopause

Performance status

- Zubrod 0-2

Life expectancy

- Not specified

Hematopoietic

- No bleeding diathesis (e.g., disseminated intravascular coagulation or clotting
factor deficiency)

Hepatic

- INR ≤ 1.6

Renal

- Not specified

Other

- HIV negative

- No other malignancy within the past 5 years except adequately treated basal cell or
squamous cell skin cancer, carcinoma in situ of the cervix, or adequately treated
stage I or II cancer currently in complete remission

PRIOR CONCURRENT THERAPY:

Biologic therapy

- No prior immunotherapy for recurrent or metastatic disease

Chemotherapy

- No prior chemotherapy for recurrent or metastatic disease

- More than 12 months since prior adjuvant or neoadjuvant chemotherapy

- No concurrent chemotherapy for malignancy

Endocrine therapy

- Prior adjuvant hormonal therapy allowed

- At least 12 months since prior adjuvant luteinizing hormone-releasing hormone (LHRH)
analogues

- Menstrual periods must not have resumed since LHRH therapy

- More than 12 months since prior adjuvant or neoadjuvant aromatase inhibitors (e.g.,
anastrozole, letrozole, or exemestane)

- More than 12 months since prior fulvestrant

- No prior hormonal therapy for recurrent or metastatic disease

- No other concurrent hormonal therapy for malignancy

- No concurrent hormone replacement therapy

Radiotherapy

- Not specified

Surgery

- Not specified

Other

- No long-term anticoagulant therapy (except antiplatelet therapy)