Abstract
Historically, metastatic breast cancer (MBC) was primarily treated with surgery and chemotherapy. To that end, a wide array of chemotherapy agents are currently available for the treatment of MBC. To date, there has been considerable progress in the understanding of the molecular underpinnings of breast cancer, which has led to the development of targeted agents. Despite this, eventually all patients with metastatic disease will receive single-agent or combination chemotherapy either to control spread or as a palliative measure. Currently, combinations of targeted agents and chemotherapy are under investigation, thereby indicating that chemotherapeutic agents will continue to be the backbone of future breast cancer therapy. However, there remains an unmet need to optimize the sequencing of chemotherapy agents based on individual patient characteristics and gene expression profiles in order to reduce toxicities and improve outcomes for patients.