Magseed Enabled Long-Term Localization of Axillary Lymph Nodes

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.

Inclusion Criteria:

- Age 18 years or older at time of consent

- Histologically confirmed cT0-4, N1 breast cancer

- Axillary lymph node metastasis with pathologic confirmation by needle biopsy

- Clip placed in the sampled axillary lymph node before initiation of chemotherapy

- Planned for neo-adjuvant chemotherapy prior to surgical resection

- Eligible for targeted axillary dissection (defined as selective localization and
removal of the clipped node and SLND) at the completion of neo-adjuvant chemotherapy

- ECOG performance status 0-2

Exclusion Criteria:

- Distant metastases

- Inflammatory breast cancer

- Prior ipsilateral axillary surgical procedure including SLND or axillary node excision

- Prior history of breast cancer in the ipsilateral breast

- History of lymphoma

- Subject is pregnant

- Previous radiation to the breast or axilla

- Pacemaker or other implantable cardiac device in the ipsilateral chest wall