This is a non-interventional study. Two PET-CT-scans are performed, one before starting treatment, and the other after 2 cycles of neoadjuvant chemotherapy. The two PET-CT-scans are prescribed by oncologists from the center of breast diseases Unit at St. Louis hospital, in Paris, France. Oncologists provide clear information to the patients on the purpose of the examination. The examinations are performed in the nuclear medicine department at St. Louis hospital. PET-CT-scans data, tumor characteristics, results of other imaging and biological tests, results of surgery and patient's follow-up are summarized in a "de-identified" file. This file has been declared to the National Commission on Informatics and Liberties (CNIL). The data in this file are established prospectively and secondary analyzed to assess the precise role of PET-CT-scans in the initial staging of breast cancer and to determine the optimal PET-CT-scans criteria to evaluate response to neoadjuvant treatment early.