[Assessment of sentinel lymph node biopsy in patients receiving neoadjuvant chemotherapy in breast cancer: before or after?]

The main goal of preoperative chemotherapy is to reduce the size of the tumor and allow conservative treatment. Neoadjuvant treatment can affect axillary status with a downstaging in one third of the cases. For these patients, the benefit of axillary node dissection is questioned and the sentinel node biopsy (SLNB) seems to be a relevant option. However, the timing of performing SLNB is still debated especially for clinical negative patients with negative axillary ultrasound before preoperative chemotherapy. For axillary positive nodes proved by biopsy/cytology before preoperative chemotherapy, SLNB can be an option if there is a good clinical and radiological response.