Radiation Therapy During Surgery in Treating Older Women With Invasive Breast Cancer

OBJECTIVES: Primary * Determine the feasibility of intraoperative partial breast radiotherapy prior to surgical resection in older women with low-risk early stage primary invasive ductal carcinoma of the breast. Feasibility will be determined by the rate of good/excellent cosmesis, as measured by the Radiation Therapy Oncology Group (RTOG) cosmetic rating scale, in patients treated with this regimen compared with that of patients treated with partial breast brachytherapy in clinical trial RTOG-9517. * Determine the incidence of grade 3-4 toxicity of this regimen in these patients. * Determine the rate of ipsilateral breast recurrence, including recurrence within the tumor bed as compared to elsewhere in the breast, in patients treated with this regimen. Secondary * Determine the radiation-induced activation of receptors and signal transduction pathways involved in radiation response in patients treated with this regimen. OUTLINE: This is a non-randomized study. Patients undergo intraoperative lymphatic mapping and sentinel lymphadenectomy OR standard level I, II axillary dissection to evaluate the lymph nodes followed by intraoperative breast ultrasonography to define the tumor target volume. Patients then undergo intraoperative single-dose partial breast radiotherapy followed by segmental mastectomy (i.e., lumpectomy) of the tumor. Patients with 1 or 2 tumor-involved surgical margins may undergo repeat segmental mastectomy. Patients with \> 2 tumor-involved surgical margins undergo mastectomy. Patients determined to have a tumor size \> 3 cm or an extensive intraductal component on final pathology evaluation undergo standard external beam radiotherapy after surgery. After completion of study treatment, patients are followed every 3 months for 2 years, every 6 months for 3 years, and then annually thereafter. PROJECTED ACCRUAL: A total of 71 patients will be accrued for this study within 2 to 3 years.