Assessment of Response to Neo-adjuvant Chemotherapy for Patients With a Locally Advanced Breast Cancer With 3D Elastography (Shear Wave), NEOELASTO

Inclusion Criteria: * Infiltrating Breast Cancer untreated and/or locally advanced (stages I (T1c), IIa IIb, IIIa, IIIb, IIIc of UICC classification), whatever histological type. * Neo-adjuvant chemotherapy decided.(Anthracyclines, taxanes and, for tumors overexpressing human epidermal growth factor receptor 2 (HER2) protein, targeted recombinant humanized monoclonal antibodies) * Index tumor whose dimensions are between 10 to 50 mm. Multifocality, and/or multicentricity and/or bilaterality accepted (maximum 2 tumors by breast et tumors well differentiated from each other). * Patients aged at least 18 years old at diagnosis * Full results conventional breast exams available and no reason to achieve MRI breast exam * Patient explanation given and consent information signed Exclusion Criteria: * Pregnant or during lactation * Personal history of ipsilateral breast cancer (ipsilateral recurrence or second cancer in the same breast). * Patient carrier of cosmetic breast implants * Person deprived of liberty or under guardianship * Contraindication for receiving neo-adjuvant chemotherapy for any medical reason * Inability to submit to medical monitoring of the trial for reasons of geography, social or psychological.