Axillary ultrasound for prediction of response to neoadjuvant therapy in the context of surgical strategies to axillary dissection in primary breast cancer: a systematic review of the current literature.

Data on the optimal treatment strategy for patients undergoing neoadjuvant therapy (NAT) who initially presented with metastatic nodes and convert to node-negative disease (cN+ → ycN0) are limited. Since NAT leads to axillary downstaging in 20-60% of patients, the question arises whether these patients might be offered less-invasive procedures than axillary dissection, such as sentinel node biopsy or targeted removal of lymph nodes marked before therapy.