Aim of the study is to investigate whether intra-surgical visualisation of malignoma reduces the resection rate in the case of R1 resection compared to the procedure without sonographic visualisation

Inclusion Criteria:

• 18 to 80 years
• Female
• Presurgical validated breast cancer
• Unifocal to multifocal findings
• Palpable and/o non-palpable findings
• Neoadjuvant chemotherapy
• Indication for breast conserving therapy
• General operation ability and anesthesia ability
• Consent to conventional breast conserving breast surgery with wire marking
• Ability and will to follow the study conditions
• Written declaration of consent after clarification

Exclusion Criteria:

• Sonographically not clearly delineate resection areal
• Exclusion criteria for breast conserving therapy
• Simultaneous participation in other interventional trials that interfere with this study at the investigator's discretion