Accelerated Partial Breast Radiation Therapy Using High-Dose Rate Brachytherapy in Treating Patients With Early Stage Breast Cancer After Surgery

Inclusion Criteria: * Must sign informed consent * Surgical treatment of the breast must have been lumpectomy; the margins of the resected specimen must be histologically free of tumor (negative surgical margins per National Surgical Adjuvant Breast and Bowel Project \[NSABP\] criteria) * On histologic examination, the tumor must be ductal carcinoma in situ (DCIS) and/or invasive breast carcinoma * For patients with invasive breast cancer, an axillary staging procedure must be performed (either sentinel node biopsy \[SNB\] alone or axillary dissection \[with a minimum of six axillary nodes removed\], and the axillary node\[s\] must be pathologically negative); patients over 70 with estrogen receptor positive (ER+) tumors no greater than 2 cm do not require axillary evaluation, but MUST be clinically node negative on examination and all available imaging (clinical N0) * The T stage must be Tis, T1, or T2; if T2, the tumor must be =\< 3.0 cm in maximum diameter * Estrogen receptor positive tumor and/or progesterone receptor positive tumor Exclusion Criteria: * Pregnant or breast-feeding * Active collagen-vascular disease * Paget's disease of the breast * Prior history of DCIS or invasive breast cancer * Prior breast or thoracic radiation therapy (RT) for any condition * Multicentric carcinoma (DCIS or invasive) * Synchronous bilateral invasive or non-invasive breast cancer * Surgical margins that cannot be microscopically assessed or that are positive * Positive axillary node(s) * T stage of T2 with the tumor \> 3 cm in maximum diameter or a T stage \>= 3 * Estrogen receptor negative and progesterone receptor negative tumor * Any of the dosimetric treatment criteria as defined have not been met; patients who become ineligible due to inability to meet dosimetric criteria should not receive treatment as defined in this protocol and will come off the study; any subsequent adjuvant radiation will be delivered at the discretion of the treating physician