S0226 Anastrozole With or Without Fulvestrant as First-Line Therapy in Postmenopausal Women With Metastatic Breast Cancer

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)