Tamoxifen Citrate or Letrozole With or Without Bevacizumab in Treating Women With Stage IIIB or Stage IV Breast Cancer

Inclusion Criteria

• Histologic confirmation of invasive cancer of the female breast in either the primary or metastatic setting
• Stage IV disease or stage IIIB disease (using American Joint Committee on Cancer [AJCC] criteria, 6th edition) not amenable to local therapy
• Patients may not have a "currently active" second malignancy other than non-melanoma skin cancers; patients are not considered to have a "currently active" malignancy if they have completed therapy and are considered by their physician to be at less than 30% risk of relapse
• Tumors (from either primary or metastatic sites) must express estrogen receptor (ER) and/or progesterone receptor (PgR) in >= 1% of cells will be considered positive
• Postmenopausal women are eligible for this trial; before study registration, menopausal status must be defined according to the criteria below:
• Age >= 55 years and one year or more of amenorrhea
• Age = 2.0 cm with conventional techniques or as >= 1.0 cm with spiral computed tomography (CT) scan
• Non-measurable disease: all other lesions, including small lesions (longest diameter 150 and/or diastolic blood pressure > 90 mmHg on antihypertensive medications or any prior history of hypertensive crisis or hypertensive encephalopathy
• History of myocardial infarction or unstable angina within past 6 months
• New York Heart Association (NYHA) grade 2 or greater congestive heart failure
• Symptomatic peripheral vascular disease
• Significant vascular disease (e.g., aortic aneurysm, aortic dissection) or arterial thrombotic events
• Full dose anticoagulation therapy is allowed for the treatment of prior conditions such as venous thrombosis or atrial fibrillation, but not for the treatment of prior arterial thrombotic events; patients on full dose anticoagulants must be on a stable dose of warfarin and have an in-range international normalized ratio (INR) (usually between 2 and 3) or be on a stable dose of low-molecular weight (LMW) heparin; patients receiving antiplatelet agents are eligible, as are patients on daily prophylactic aspirin or anticoagulation for atrial fibrillation
• Patients may not have a history of stroke or transient ischemic attack within 6 months prior to study registration
• Patients with a history of seizures must be well controlled with standard medication
• Patients must not have known central nervous system (CNS) metastases or leptomeningeal disease (screening with brain imaging is not required for asymptomatic patients)
• In aromatase inhibitor (AI)-treated patients: no known allergies to imidazole drugs, (e.g. clotrimazole, ketoconazole, miconazole, econazole, sulconazole, tioconazole, or terconazole) or compounds structurally similar to bevacizumab
• In tamoxifen treated patients: no known allergies to selective estrogen receptor modulators (e.g. tamoxifen, raloxifene or toremifene) or compounds structurally similar to bevacizumab; for patients enrolled after Update #5, endocrine therapy will consist of letrozole only and this criterion will no longer apply
• Eastern Cooperative Oncology Group (ECOG) (Zubrod) performance status = = 12 weeks
• All patients who are premenopausal (if not already receiving ovarian suppression therapy/surgical oophorectomy) must have a negative beta-human chorionic gonadotropin (beta-Hcg) prior to starting on study treatment; patients may not be pregnant or nursing at any time during the study; ovarian suppression is required in women of childbearing potential by the start of protocol therapy, and will continue for the duration of protocol therapy
• Granulocytes >= 1,000/ul
• Platelet count >= 100,000/ul
• Creatinine = = 2+ proteinuria at baseline must undergo a 24-hour urine collection that must demonstrate < 1 g of protein/24 hr, or UPC ratio < 1 to allow participation in the study