Fulvestrant With or Without Anastrozole or Exemestane Alone in Treating Postmenopausal Women With Locally Advanced or Metastatic Breast Cancer

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed adenocarcinoma of the breast Locally advanced or metastatic disease Metastatic disease must be measurable or evaluable Patients with bone only metastases are eligible provided there is an evaluable site of bone metastasis that can be followed by x-ray, MRI, or CT scan Relapsed or progressed during prior treatment with single-agent nonsteroidal aromatase inhibitor (NSAI)*, meeting either of the following criteria: NSAI given as adjuvant therapy that lasted ≥ 12 months Achieved an objective complete response, partial response, or stable disease that lasted ≥ 6 months after prior first-line therapy with NSAI for locally advanced or metastatic disease Chemotherapy as part of the first-line therapy given before initiation of NSAI allowed NOTE: *Patients are required to continue to take NSAI until beginning of study treatment. No rapidly progressive visceral disease (i.e., lymphangitis carcinomatosa or diffuse hepatic involvement) Hormone receptor status: Estrogen receptor (ER) and/or progesterone receptor positive tumor No ER-unknown disease PATIENT CHARACTERISTICS: Sex Female Menopausal status Postmenopausal, as defined by 1 of the following criteria: Age 60 and over Age 45 to 59 AND ≥ 12 months since last menstrual period with no prior hysterectomy Any age with prior bilateral oophorectomy Performance status WHO 0-2 Life expectancy More than 3 months Hematopoietic Neutrophil count ≥ 1,500/mm^3 Platelet count ≥ 100,000/mm^3 No thrombocytopenia Hemoglobin ≥ 10 g/dL Hepatic AST and ALT ≤ 2.5 times upper limit of normal (ULN) Alkaline phosphatase ≤ 5 times ULN (unless due to bone metastases) No liver disease Renal Creatinine < 1.97 mg/dL Other No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer or carcinoma in situ of the cervix PRIOR CONCURRENT THERAPY: Chemotherapy See Disease Characteristics Prior neoadjuvant or adjuvant chemotherapy allowed Endocrine therapy See Disease Characteristics Prior tamoxifen as neoadjuvant or adjuvant therapy allowed No systemic corticosteroids that lasted > 15 days within the past 4 weeks Other More than 4 weeks since prior investigational drugs Concurrent bisphosphonates for bone metastases allowed provided bisphosphonate therapy has been established for ≥ 6 months Concurrent initiation of bisphosphonate allowed provided patient has soft tissue or visceral metastases as the measurable or evaluable target lesion No concurrent anticoagulant therapy No concurrent unlicensed noncancer investigational agents