Radiation therapy is an integral part or the management of early stage breast cancer. At least 5 other randomized trials have firmly established the role of radiation in breast conserving therapy (BCT). Traditionally, BCT consist of limited surgery and whole breast radiation. Although this treatment provides excellent local control and equivalent survival to modified radical mastectomy (MRM) in appropriately selected patients, this achievement is not without physical and social costs. Specifically the physical cost of radiation includes but is not limited to skin damage, rib fracture, lung damage, heart damage, pain and poor cosmesis. There are also social costs. Radiation in BCT is typically given daily for 5-7 weeks. This results in lost time from loved ones and livelihood. Additional time is lost when patients often have to travel great distances to the nearest radiation oncology center. The fear of side effects of whole breast radiation and the inconvenience of a 7-week treatment schedule, force women who are candidates for BCT, to choose MRM and therefore suffer an unnecessary anatomical loss.

To allow greater freedom of choice in local therapy, much research has gone into developing altered breast-conserving therapies that would provide the same local control and survival but at much lower social and physical cost. This research has basically taken two paths: 1) shorten the course of therapy and 2) decrease the amount of breast treated.