An Observational Study of Current Practice Pattern on the Treatment of Women With Metastatic Breast Cancer Whose Tumors Overexpress Her2neu

In clinical practice, patients with metastatic breast cancer are being treated either with trastuzumab alone or trastuzumab in combination with chemotherapy or hormonal therapy as it has shown to increase survival. There is currently minimal information as to how long trastuzumab should be given after disease progresses on trastuzumab. This study is a chart review of the above-mentioned population which will capture information such as; * what chemo or hormonal therapies are chosen by clinicians for Her-2 positive metastatic patients to combine with trastuzumab * what the number of treatment regimens are (chemo or hormonal) given with trastuzumab * what the clinical outcome of patients treated is * what happens to the patients cardiac status with long term administration of trastuzumab * what treatment patterns exist in the management of central nervous system metastases This study aims to generate a hypotheses that can be tested from the information collected after is has been analyzed to give clinicians further meaningful data to guide treatment decisions beyond treatment progression.