Comparison of Axillary Lymph Node Dissection With Axillary Radiation for Patients With Node-Positive Breast Cancer Treated With Chemotherapy

Pre-Registration Eligibility Criteria: * Clinical stage T1-3 N1 M0 breast cancer at diagnosis (prior to the start of neoadjuvant chemotherapy) by American Joint Committee on Cancer (AJCC) staging 7th edition * No inflammatory breast cancer * No other malignancy within 5 years of registration with the exception of basal cell or squamous cell carcinoma of the skin treated with local resection only or carcinoma in situ of the cervix * All patients must have had an axillary ultrasound with fine needle aspiration (FNA) or core needle biopsy of axillary lymph nodes documenting axillary metastasis at the time of diagnosis, prior to or at most 14 days after starting neoadjuvant chemotherapy \* Note: Biopsy of intramammary nodes does not fulfill eligibility criteria * Patients must have had estrogen receptor, progesterone receptor and HER2 status (by immunohistochemistry \[IHC\] and/or in situ hybridization \[ISH\]) evaluated on diagnostic core biopsy prior to start of neoadjuvant chemotherapy \* Note: If HER2 status has not been clearly determined (i.e. equivocal/indeterminate), then patients should not be enrolled * Patients must have completed all planned neoadjuvant chemotherapy prior to surgery; sandwich chemotherapy is not allowed (i.e. anthracycline/cytoxan or taxane chemotherapy planned to be given after surgery); patients must have completed at least 4 cycles of neoadjuvant chemotherapy consisting of an anthracycline and/or taxane-based regimen without evidence of dise…