This is a post-market, prospective, open-label, single arm study of Magseed and Sentimag in patients with breast cancer with biopsy-proven axillary node metastases who had a clip placed to mark the metastatic node and are having that clipped node selectively removed at surgery following neo-adjuvant chemotherapy (NAC). Subjects will have the Magseed placed to mark axillary lymph nodes with biopsy-proven metastasis under ultrasound guidance before initiating NAC. After completion of NAC, the Magseed will be localized using the Sentimag system during surgery and removed with the targeted lymph node.
