Estradiol Suppression for the Treatment of Metastatic Breast Cancer in Premenopausal Women

INCLUSION CRITERIA * Histologically-confirmed, bi-dimensionally measurable, recurrent or metastatic carcinoma of the breast that is progressive * Premenopausal, defined as any of: 1. Last menstrual period within 3 months, or 2. Post-hysterectomy without bilateral oophorectomy and with follicle-stimulating hormone (FSH) in the premenopausal range, or, 3. If tamoxifen administered within the past 3 months, plasma estradiol must be in the premenopausal range * Either positive estrogen and/or progesterone receptor determination by Immunohistochemistry (IHC) or competitive binding assay on metastatic disease, or if not performed on their metastatic disease a positive result on their primary breast cancer specimen. * Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2 * Granulocytes \> 1500/mm\^3 * Platelets \> 100,000/mm\^3 * Serum glutamic oxaloacetic transaminase (SGOT) \< 2.5 x upper limit of normal * Total bilirubin \< 1.5 mg/dL * May have received irradiation to bony sites of disease for pain control or for prevention of fracture. The irradiated site(s) will NOT be evaluable for disease response. * Must be using effective contraception or not be of childbearing potential * Signed written informed consent INCLUSION CRITERIA * Active, unresolved infection * Active malignancy other than breast cancer, in situ carcinoma of the cervix, or non-melanomatous skin cancers in the past 5 years * Prior treatment with an aromatase inhibitor or inactivator * Prior treatment with an luteinizing hormone-releasing hormone (LH/RH) agonist/antagonist * Adjuvant chemotherapy within 6 months of study entry. * Received chemotherapy or hormonal therapy in the 3 weeks prior to enrollment * Central nervous system metastasis * Lymphangitic pulmonary metastasis * Pregnant or lactating