Magnetic versus standard technique for sentinel node biopsy in breast cancer

INTERVENTION: SLNB with the standard combined technique (blue dye and radioisotope) or the new technique (magnetic tracer and hand‐held magnetometer). Interventions are the injection of the radioisotope, blue dye and magnetic tracer. Furthermore, the detection and localization of the sentinel lymph node with gammaprobe (standard arm) or the hand‐held magnetometer (magnetic arm). CONDITION: Breast cancer ; Cancer ; Malignant neoplasm of breast PRIMARY OUTCOME: 1. Overall SLNB identification rate (proportion of successful SLNBs) with either the standard or the new technique ; 2. SLNB identification rate within the cohort of patients with involved nodes SECONDARY OUTCOME: 1. Morbidity from SLNB (including staining and lymphoedema rate); 2. Locoregional recurrence; 3. Cost effectiveness (health economics) ; 4. Patient‐reported outcome measures (PROMS) with both techniques INCLUSION CRITERIA: Patients with breast cancer scheduled for SLNB and who are clinically and radiologically node negative