Dear marylindaleon, The goal of treatment of metastatic breast cancer is to control the disease and symptoms of the disease for as long as possible. Decisions about treatment need to take into account many factors not strictly a rising ca27.29 level. These factors include tolerance of treatment, symptoms, evidence of disease, prior treatments. All of this is put into context of the individual patient. Arimidex is a treatment used for postmenopausal hormone receptor positive breast cancer. Individuals with hormone receptor positive tumors that are also Her2neu positive may not have as prolonged a response to the hormonal treatments than those with hormone receptor positive, Her2 negative tumors. Frequently, the drug trastuzumab is included in the treatment of Her2+ breast cancer -often in combination with chemotherapy. You should discuss with your oncologist what treatment options are appropriate for your situation.