Evaluation of Magseed as Localization Device for Biopsy Proven Metastatic Axillary Lymph Nodes

Part 1: Ten women with biopsy proven breast cancer and metastasis to an axillary lymph node will have a Magseed placed into the metastatic lymph node AFTER neoadjuvant chemotherapy (NAC) and just prior to surgery. These patients will have a non-contrast enhanced breast MRI development study to evaluate and identify ways to reduce the artifact in the axilla created by the Magseed. Efficacy of the localization with the Magseed will be available within a week of the placement. Part 2: Ten additional women with biopsy proven breast cancer and metastasis to an axillary lymph node will have a Magseed placed into the metastatic lymph node BEFORE NAC. These patients will have routine contrast enhanced MRIs, mammograms, and ultrasounds before and after NAC to evaluate treatment response. Seed placement: Once a patient has been identified eligible for the research study and has provided written informed consent the patient will have a Magseed placed into the biopsy proven lymph node. The Magseed delivery system is identical to the investigators' current practice using radioactive seeds. The seed is pre-loaded into the needle and is inserted into the lymph node following local anesthesia with 1% lidocaine. Once the seed is deployed, post procedure seed location is confirmed sonographically and mammographically with tomosynthesis. MRI: Ten no-charge limited non-contrast breast MRIs for research development purposes are available for this study through the radiology department. Phase 1 participants will enroll in the study after their pre- and post-NAC imaging has already been performed per routine clinical practice. These participants will have a single non-contrast enhanced breast MRI using the investigators' standard non-contrast sequences (axial ideal T1 and T2-weighted, axial Short-TI Inversion Recovery (STIR), and axial 3D vibrant using a dedicated breast coil, FOV 28 cm or to fit the patient size, and an image-thickness/image-increment of 5mm/1mm). A physicist will participate in the scanning of these patients to evaluate the extent of artifact in the axilla and adjacent breast tissue and optimize scanning parameters to reduce this artifact. Phase 2 participants will enroll in the study prior to NAC and have routine contrast enhanced breast MRIs performed before and after NAC. Clinically indicated MRI scans will be charged to the patient's insurance company as this imaging is standard clinical practice. The MRI protocol will use the investigators' standard clinical sequences (axial ideal T1 and T2-weighted, axial STIR, and axial 3D vibrant using a dedicated breast coil). Once contrast is injected (gadobutrol 10mmol/10mL) 3D vibrant sequences will be obtained four times after contrast injection (FOV 28 cm or to fit the patient size, and an image-thickness/image-increment of 5mm/1mm). Mammogram: Patients enrolled in the research study will have standard mammographic imaging before and after NAC, which will include both the breast and axilla as per routine clinical protocol. Ultrasound: Patients enrolled in the research study will have standard sonographic imaging before and after NAC of the breast and axilla as per routine clinical protocol. Post-NAC ultrasound of the axilla will be a supplemental assessment to breast MRI as the Magseed artifact may obscure these findings. Seed Removal: As per the current practice, patients will have targeted axillary lymph node dissection including both the localized lymph node and sentinel lymph node. Identifying the lymph node containing the Magseed will require the Sentimag handheld probe in the operating room. This device which functions similar to the gamma probe has been approved for an equipment trial starting in August of 2018. Once the lymph node has been excised a specimen radiograph will be obtained to verify removal.