Using the Conture® Multi-Lumen Balloon to Deliver Accelerated Partial Breast Brachytherapy

Inclusion Criteria: * Able and willing to sign informed consent * Age 50 or older at diagnosis * Life expectancy greater than 10 years (excluding diagnosis of breast cancer). * 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 NSABP criteria). * On histologic examination, the tumor must be DCIS or invasive breast carcinoma. For patients with invasive breast cancer, an axillary staging procedure must be performed. Either: 1. sentinel node biopsy (SNB) alone if sentinel node(s) is/are negative; or 2. axillary dissection (minimum of six axillary nodes removed); and 3. the axillary node(s) must be pathologically negative. * 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 Exclusion Criteria: * Age \< 50 at diagnosis (regardless of histology) * Pregnant or breast-feeding (if appropriate, patient must use birth control during the study) * Active collagen-vascular disease * Paget's disease of the breast * History of DCIS or invasive breast cancer * Prior breast or thoracic 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 or close * Positive axillary node(s) * T stage of T2 with the tumor \> 3 cm in maximum diameter or a T stage \> 3 * Estrogen receptor negative tumor