Update on accelerated partial-breast irradiation.

Progress in radiotherapy technology, particularly the advent of CT-guided simulation and three-dimensional conformal planning, has given the radiation oncologist the ability to precisely treat part of the breast, instead of the whole breast, using either brachytherapy or external-beam techniques. Treating such a limited area may allow the course of treatment for patients with early-stage breast cancer to be drastically shortened and could reduce toxicity to other organs. This article summarizes the rationale for accelerated partial-breast irradiation (APBI), techniques for performing it, and outcome to date of studies of APBI.