The goal of this clinical trial is to intraoperatively visualize tumour tissue in breast cancer patients using fluorescence imaging with the tracer bevacizumab-IRDye800CW and thereby enhance real-time clinical decision making, preventing postoperative tumour-positive margins.

Inclusion Criteria:

• Patients are females with histologically proven carcinoma of the breast
• The carcinoma of the breast is a local disease with limited size (but tumor size ≥ 0.5cm) and in the multidisciplinary tumor board meeting breast conserving therapy is advised.
• Age ≥ 18 years
• Written informed consent has been obtained
• Women of childbearing potential (premenopausal women with intact reproductive organs and women less than two years after menopause) require use of effective contraception at least 3 months before administration of the tracer (if not, a negative serum pregnancy test has to be submitted), and they need to be willing to ensure that she or her partner uses effective contraception during the trial and for 3 months thereafter.

Exclusion Criteria:

• Medical or psychiatric conditions that compromise the patient's ability to give informed consent
• Non palpable breast tumor or prior surgery of this breast
• Received an investigational drug within 30 days prior to bevacizumab-IRDye800CW
• History of myocardial infarction, cerebrovascular accident, uncontrolled cardiac heart failure or unstable angina within 6 months prior to enrollment
• Inadequately controlled hypertension with or without current antihypertensive medication
• Significant renal or hepatic impairment (grade II or higher deviations by CTCAE)
• History of allergy or infusion reactions bevacizumab or other monoclonal antibodies
• Pregnant or lactating women
• Patients receiving Class IA (quinidine, procainamide) or Class III (dofetilide, amiodarone, sotalol) antiarrhythmic agents
• Life expectancy < 12 weeks
• Preoperatively undetectable lymph nodes using SPECT-scan, requiring the use of patent blue