Neoadjuvant chemotherapy, also termed primary, induction, or preoperative chemotherapy, is defined as chemotherapy administered before locoregional treatment. It was first used in locally advanced breast cancer 30 years ago. Classically, these tumors were treated with radical surgery and/or radiotherapy. However, despite this aggressive local therapy, most patients relapsed with distant metastases and eventually died. The aim of neoadjuvant therapy is to reduce the tumor volume in patients before surgical resection, thus increasing the likelihood of breast conservation. More recently, neoadjuvant therapy has been studied as a way of testing the relevance of biological markers in predicting disease outcome.