Status of accelerated partial breast irradiation

Breast-conserving therapy is accepted as a standard of care option for patients with early-stage breast cancer. However, studies examining patterns of failure after treatment suggest that a lengthy course of adjuvant whole breast irradiation delivered as a component of breastconserving therapy may not always be necessary; indeed, in appropriately selected patients, radiation therapy delivered only to the tumor bed may be acceptable. Several modalities of delivering accelerated partial breast irradiation (APBI) have been developed, the most prevalent being multi-catheter interstitial brachytherapy, the MammoSite breast brachytherapy catheter (Hologic Corporation, Bedford, MA) and three-dimensional conformal external-beam radiation therapy. The purpose of this article is to review the published experiences on the most common modalities of delivering APBI and to outline the current open national phase 3 trial. To date, phase 1/2 studies have demonstrated excellent local control and cosmetic outcomes in earlystage breast cancer patients treated with APBI. As increasing knowledge is accumulated regarding the efficacy and safety of APBI, a consensus will emerge regarding its potential replacement of whole breast irradiation in selected early-stage breast cancer patients. © Springer Science+Business Media, LLC 2010.