Patient description: The patient is a 42 year-old postmenopausal woman who had a screening sonogram which revealed an abnormality in the right breast. She had no palpable masses on breast exam. Core biopsy was done and revealed a 1.8 cm infiltrating ductal breast carcinoma in the left upper outer quadrant. Lumpectomy was done and the surgical margins were clear. The tumor was HER2-positive and ER/PR negative. Axillary sampling revealed 1 positive lymph node out of 12 sampled. CXR was unremarkable. She is using “well women” multivitamins daily and no other medication. She smokes frequently and consumes alcohol occasionally. She is in a relation with only one partner and has a history of 3 pregnancies and live births. She breastfed all three children.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Invasive Breast Carcinoma Stage 0 Breast Cancer AJCC v6 and v7 Stage I Breast Cancer AJCC v7 Stage IA Breast Cancer AJCC v7 Stage IB Breast Cancer AJCC v7 Stage II Breast Cancer AJCC v6 and v7 Stage IIA Breast Cancer AJCC v6 and v7 Stage IIB Breast Cancer AJCC v6 and v7 Stage III Breast Cancer AJCC v7 Stage IIIA Breast Cancer AJCC v7 Stage IIIB Breast Cancer AJCC v7 Stage IIIC Breast Cancer AJCC v7 Triple-Negative Breast Carcinoma STEP 1 Patients must have histologically confirmed estrogen receptor (ER)-, progesterone receptor (PR) and HER2-negative (triple-negative, TNBC) or ER-, PR weakly positive and/or HER2 equivocal status and must not have received and not be planning to receive adjuvant anti-HER2 or endocrine therapies after completion of neoadjuvant chemotherapy; patients who are HER2-positive by American Society of Clinical Oncology (ASCO) College of American Pathologists (CAP) guidelines are ineligible; HER2-negative and HER2-equivocal cases as per ASCO CAP guidelines that do not receive HER2-targeted therapy are eligible; patients with weakly ER or PR positive disease, defined as ER and/or PR less than or equal to (=<) 5% by immunohistochemistry, are eligible if the treating physician considers the patient not eligible for adjuvant endocrine therapy; residual disease must be >= 1 cm in greatest dimension, and/or have positive lymph nodes (ypN1mi, ypN1, ypN2, ypN3) observed on pathologic exam NOTE: If the ER and/or HER2 results are discordant between the initial, pre-chemotherapy, and post-chemotherapy surgical tissue, the receptor status of the residual disease has to be used to determine eligibility. Immunohistochemistry (IHC)-positive isolated tumor cells in the lymph node (N0 [i+]) are not considered node-positive and these patients also must have >= 1 cm residual invasive cancer in the breast to be eligible Patients must not have metastatic disease (i.e., must be clinically M0 or Mx; systemic staging studies with imaging should follow routine practice as per National Comprehensive Cancer Network [NCCN] and ASCO guidelines); patients must not have locally recurrent disease It is preferred that axillary lymph node sampling is performed after completion of neoadjuvant chemotherapy to allow more accurate assessment of pathologic response; complete axillary lymph node dissection (ALND) after neoadjuvant chemotherapy is recommended in the following situations Patients had documented pathologic involvement of the axillary nodes (fine needle aspiration [FNA] or core biopsy) before neoadjuvant chemotherapy and had sentinel node biopsy after neoadjuvant chemotherapy with positive sentinel node(s) Patient had documented pathologic involvement of the axillary nodes (FNA or core biopsy) before neoadjuvant chemotherapy and had only 1 sentinel lymph node removed after neoadjuvant chemotherapy