The purpose of this research study is to determine how feasible and accurate identifying and removing specific lymph nodes in the axilla (armpit) after neoadjuvant systemic therapy is when patients present with breast cancer that has spread to lymph nodes in the axilla. The specific lymph nodes removed would be determined at the time of diagnosis. If a biopsy proves that cancer has spread to a lymph node, a titanium clip will placed in it to mark it for future removal. That lymph node will be removed after systemic therapy and compared with the rest of the lymph nodes removed from that region.

Inclusion Criteria:

1. Histologic diagnosis of invasive breast cancer, clinical stage T0-3 N1-3 (maximum three abnormal axillary nodes on ultrasound exam) M0.
2. Core needle biopsy (or fine needle aspiration (FNA)) of an axillary node documenting nodal disease at time of diagnosis and prior to preoperative systemic therapy or surgery. Clinical care marker clip placed in the abnormal axillary nodes identified at ultrasound at the time of core needle or FNA of an axillary node that documented nodal disease.
3. Subjects must be undergoing neoadjuvant systemic therapy (or have just completed it) prior to the surgical intervention.
4. No prior axillary lymph node surgery for pathological confirmation of axillary status.
5. No nitinol (nickel-titanium) allergy. The Savi Scout ® marker device contains nitinol.
6. Females of childbearing potential must have a negative serum pregnancy test within 14 days prior to receipt of chemotherapy. NOTE: Females are considered of child bearing potential unless they are surgically sterile (have undergone a hysterectomy, bilateral tubal ligation, or bilateral oophorectomy) or they are naturally postmenopausal for at least 12 consecutive months
7. Females of childbearing potential must be willing to abstain from heterosexual activity or to use 2 forms of effective methods of contraception from the time of informed consent until 30 days after chemotherapy discontinuation. The two contraception methods can be comprised of two barrier methods, or a barrier method plus a hormonal method or an intrauterine device that meets <1% failure rate for protection from pregnancy in the product label.
8. As determined by the enrolling physician or protocol designee, ability of the subject to understand and comply with study procedures for the entire length of the study.

Exclusion Criteria:

1. Active infection requiring systemic therapy
2. Has a known additional malignancy that is active and/or progressive requiring treatment; exceptions include basal cell or squamous cell skin cancer, in situ cervical or bladder cancer.
3. Any distant metastasis by imaging and biopsy (cM1)
4. Patients not receiving neoadjuvant systemic therapy.