Accelerated Partial Breast Irradiation As a Part of Breast Conservation Therapy

Abstract

Historically, the treatment paradigm for early-stage breast cancer has included treatment of the whole breast. Breast conservation therapy (BCT), irradiation of the whole breast following lumpectomy, requires daily treatment for 6 to 6.5 weeks. Although this is a successful and welltolerated treatment, many patients choose to avoid whole breast irradiation as a result of the time and travel difficulties they are unable to overcome. In response, accelerated partial breast irradiation (APBI) has been investigated as a possible alternative to conventional postlumpectomy treatment. By limiting the volume of breast tissue targeted for treatment, the present data suggests that the radiation dose delivery can be safely accelerated and reduced to a treatment time of 5 days. As a result, APBI has the potential to provide more women with an alternative BCT option. This report reviews the background, concepts supporting APBI, treatment techniques used, available data from single institutional studies, and the details of presently active and planned phase III trials. The compilation of the currently available results supports the national phase III trial (National Surgican Adjuvant Breast and Bowel Project [NSABP] B39/Radiation Therapy Oncology Group [RTOG] 0413), which will begin soon, and practitioners are urged to contribute patients. Both inside and outside the trial, a meticulous quality assurance program is required for optimal results using APBI. The importance of future investigation to establish the limitations of this new treatment approach and to define the role of specific treatment techniques is emphasized.