The evolving role of partial breast irradiation in early-stage breast cancer.

Whole breast irradiation (WBI) over 5-7 weeks has long been considered standard adjuvant treatment after breast-conserving surgery. Recently the concept of irradiating the whole breast has been challenged by accelerated partial breast irradiation (APBI), which exclusively targets the lumpectomy site plus margin. We review the evidence supporting APBI from modern clinical trials, the pros and cons of various APBI techniques, and the controversies regarding the applicability of APBI to specific patient groups.