PET-CT in the Initial Staging of Breast Cancer and in the Early Assessment of Response to Neoadjuvant Chemotherapy

The two main objectives of this prospective study are: * to identify those patients for whom pre-treatment FDG (Fluorodeoxyglucose) PET (positron emission tomography) CT-scan (Computed tomography scan) provides useful information for the treatment of breast cancer (ASAINT 1), * to improve FDG PET-CT-scan imaging criteria for assessing response to neoadjuvant therapy early, in M0-patients (ASAINT 2). The secondary objective is to better understand the interactions between the imaging parameters of FDG PET-CT-scan and biological and histological features of breast cancer . 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.