In a general radiation oncology practice, breast cancer typically comprises approximately 25% of the total patient caseload.1 Surgery is the primary modality of treatment. Radical mastectomy remained the mainstay of surgical therapy into the 1970s. Breast-conserving surgery followed by radiation therapy to the intact breast is an established standard of care for the majority of women with early stage invasive breast cancer. Recommended techniques for breast-conservation treatment are local excision of the primary tumor, preferably with clear margins, axillary lymph node dissection, and breast irradiation (45 to 50 Gy), usually with a boost (10 to 20 Gy, depending on tumor size and status of the surgical margins).