Treatment of T1N0 Invasive Breast Carcinoma by Local Excision Implant

Inclusion Criteria: * Low risk of multifocal disease within the breast whose tumor location is favorable for brachytherapy catheter placement * Diagnosis of invasive breast carcinoma (biopsy or fine needle aspiration cytology) and be clinical stage T1N0 (primary tumor \< 2cm, clinically negative nodes) * Location of primary tumor is not immediately adjacent to the nipple of chest wall * No evidence of two or more separate tumors within the breast * All histologic types and pathologic grades of primary tumor * No extensive intraductal component (substantial intraductal carcinoma away from the primary tumor location) * No lymphatic or vascular invasion * Lymph node staging by sentinel node excision or axillary dissection confirms node negative status (If node positive, implant is used to deliver boost to tumor bed) * Assessment of final surgical margins should be predominantly negative, but a single small region of focal positivity is allowable as it is for whole breast radiation * 18 years of age or older Exclusion Criteria: * Tumor is too close to the chest wall to allow placement of catheters * Contraindications to radiation therapy are present, including a history of scleroderma, systemic lupus or other active connective tissue disease, pregnancy, or prior chest wall radiation