Inclusion Criteria:

• * Women or men greater than or equal to 18 years.
• * Histologically confirmed invasive adenocarcinoma of the breast.
• * Clinical T0-4 N2-3 M0 at diagnosis (American Joint Committee on Cancer, 7th Edition)
• * Assessment for cN2 disease will be performed by clinical exam and imaging. Patients should have pathologic level 1 and/or 2 axillary lymph nodes which are fixed/matted on physical exam.
• * Cross-sectional imaging will be used to identify advanced nodal disease involving the axilla, infraclavicular, supraclavicular, and internal mammary regions, cN3 disease.
• * Patients must have biopsy proven involvement of the axillary lymph nodes.
• * Receipt of standard multiagent chemotherapy +/- targeted therapy based on tumor subtype.
• * Candidate for surgical management of breast cancer.
• * Ability to understand and willingness to sign a written informed consent document.

Exclusion Criteria:

• * History of allergic reactions or hypersensitivity to radioactive lymph node mapping agents or blue dye.
• * Pregnancy.