Refining Local-Regional Therapy for IBC

Inclusion Criteria: * Stage III IBC (cT4d cN0-2). Inflammatory breast cancer is defined as the following constellation of symptoms (all of the following must be met): * Rapid onset symptoms (6 months or less from time of diagnosis) * Breast erythema, edema and/or peau d'orange and/or warm breast with or without an underlying palpable mass * Erythema occupying at least one-third of the breast * Pathologic confirmation (biopsy-proven) invasive breast carcinoma * Women age ≥18 years * ECOG performance status ≤2Performance status * Ability to understand and willingness to sign informed consent document and comply with study procedures, including baseline research biopsy. If the research biopsy is not felt to be reasonably safe or feasible, a waiver must be obtained from the Principal Investigator. A formal exception would not be required in this case. Exclusion Criteria: * Participants who initiated pre-operative/neoadjuvant therapy prior to registration are ineligible. * Participants with Stage IV (metastatic) breast cancer are excluded. The absence of any evidence of distant disease on staging studies needs to be confirmed at the time of diagnosis (within 42 days from initial presentation) using the staging studies that are standard for the participating institution. * Participants with positive contralateral axillary nodes identified on standard imaging studies (MMG, MRI, US) are excluded. In participants with clinically suspicious axillary nodes, US guided biopsy will be performed prior to registration. If the contralateral axillary biopsy is positive, patients will not be eligible. If standard imaging does not identify contralateral disease yet drainage to the contralateral axillary basin is identified on pre-NAC lymphoscintigraphy, contralateral axillary US (if not already performed) will be obtained and any suspicious contralateral axillary nodes will undergo US guided biopsy. If the contralateral axillary biopsy is positive, patients will not continue on study for the evaluation of the primary endpoint, but their data will be used for the descriptive analyses of lymphatic drainage patterns in IBC. Contralateral invasive breast cancer without axillary involvement or in-situ carcinoma in either breast is allowed.