Inclusion Criteria:  Patients diagnosed with cT1-3N1M0 breast cancer, histopathologically confirmed. Age greater than or equal to 18 years and less than or equal to 85 years. Necessity and agreement to neoadjuvant chemotherapy  Exclusion Criteria:  Previous surgery ipsilateral axillary or radiation ipsilateral axillary / chest. Extranodal metastases M1 cN2-3 status Breast cancer with direct invasion of chest wall and / or skin cT4 Disease progression (clinical /radiological) under neoadjuvant treatment Pregnancy Presence of a pacemaker in the ipsilateral chest wall