Cytotoxic chemotherapy is a mainstay of treatment for advanced breast cancer. Treatment of metastatic (also called stage IV, advanced, or recurrent) breast cancer is not considered curative. Rather, the goals of treatment with chemotherapy are to prolong survival, alleviate or prevent tumor-related symptoms or complications, and improve quality of life. While the purpose of chemotherapy is to prevent or alleviate symptoms, chemotherapy paradoxically carries considerable toxicities that cause substantial symptoms in patients, notoriously including fatigue, nausea, vomiting, diarrhea, hair loss, mucositis, neutropenia, and neuropathy. Balancing the benefits and the side effects of chemotherapy is further complicated by the natural history of advanced breast cancer, which can be quite prolonged and typically involves multiple lines of chemotherapy, especially in patients whose tumors respond to treatment.