An Observational Study of Treatment Patterns and Safety Outcomes for Metastatic or Locally Recurrent Breast Cancer (VIRGO)

This is a multicenter, prospective observational cohort study (OCS) designed to follow patients with locally recurrent or metastatic breast cancer in the United States. Two cohorts will be included: * Patients with human epidermal growth factor receptor 2-negative (HER2-negative) disease receiving their first cytotoxic chemotherapy and/or targeted therapy (approximately 825 patients) * Patients with hormone receptor-positive (HR-positive) disease receiving their first hormonal therapy for advanced disease (approximately 425 patients) Patients who have received any chemotherapy for advanced disease more than 8 weeks prior to enrollment to this OCS will not be eligible. A total of approximately 1,250 patients will be enrolled. Approximately 150 study sites will be activated in order to achieve complete enrollment by December 2010.