TAD in Primary Breast Cancer With Initially ≥ 3 Suspicious Lymph Nodes

Inclusion Criteria: * signed informed consent form * female/male patient aged ≥ 18 years * clinical (c) tumor stage T1-4c, bilateral breast cancer and multifocal tumor allowed * invasive breast cancer confirmed by core biopsy * clinically node positive (cN+) (by means of axillary ultrasound or other imaging methods) with ≥ 3 clinically suspicious lymph nodes * biopsy-proven axillary lymph node involvement * marking (e.g. with a clip, magnetic seed, carbon suspension) of the clinically suspicious lymph node(s) before the start of NST * without distant metastases * indication for NST including chemotherapy * TAD + ALND planned * at least 7 lymph nodes (TAD + ALND) planned for histological analysis Exclusion Criteria: * cN0 or cN+ with ≤ 2 clinically suspicious lymph nodes * patients without indication for NST or NST \< 12 weeks * NST without chemotherapy * adjuvant/ neoadjuvant therapy already started prior to inclusion in the study * patients for whom only ALND is planned * ycN+ (by means of axillary ultrasound or other imaging methods) * recurrent breast cancer * larger surgery of the breast (starting from quadrant resection) or the axilla prior to the study * previous radiotherapy of the breast or axilla * inflammatory breast cancer * extramammary breast cancer * pregnant women * not able to undergo surgery * inability to understand the purpose of the clinical study or to comply with study conditions