Breast cancer radiotherapy: controversies and prospectives

Abstract

WBI takes 5–7 weeks, with attendant costs and inconveniences. This represents a significant hardship to certain subsets of patients and leads to disparity in breast cancer treatment. Obstacles such as inability to find an X-ray telescope (XRT) center close to home, difficulty in finding transportation to and from a center, lack of family support, and extreme age and/or physical handicap prevent some patients from electing to enter a 6-week course of WBI. Results from the breast-conserving therapy (BCT) trials suggest that up to 86% of the risk for ipsilateral breast cancer recurrence resides in close proximity to the original tumor site. This leads investigators to consider the role of an accelerated and more tumor bed-focused course of radiotherapy. APBI involves the treatment of a limited volume of breast tissue with a dose of irradiation per fraction increased and the treatment time course decreased. The goal is to deliver a dose of irradiation to a limited volume in less time, that is equivalent to the clinical outcome of the conventional 6-week treatment. 8 The importance of proper patient selection cannot be over-stressed when discussing the efficacy of APBI. This includes early stage breast cancer as determined by tumor size less than 2–3 cm, node-negative disease, age of patients more than 45–50 years, and tumor-free margins. 9,10 Additional criteria under study include features such as lobular histology, presence of extensive intraductal component (EIC), lymphvascular invasion, tumor grade and limited node-positive disease. When the tumor histology demonstrates a higher risk for multicentric disease and thus a higher rate for non-tumor bed cancer recurrence, the patients should not be