RESEARCH Proton radiotherapy for ch

cally advanced breast cancer (LABC) [1]. Unfortunately, radiation to the chest wall and regional lymphatics car-ries risks of cardiopulmonary and other toxicities [2]. Al-though modern techniques minimize high dose radiation to avoidance structures, some patients with advanced disease and/or unfavorable anatomy still present a chal-lenge for radiation planning and compromises in target Proton radiation is a form of particle radiation capable of delivering therapeutic radiation with complete sparing of tissues beyond the target. Mainly due to patient ca-pacity limits in the relatively small number of clinical proton facilities, the clinical use of protons has been li-mited to tumors requiring high doses or to those in close proximity to critical structures (e.g. brain, spinal cord). Despite substantial capital and operational costs, several proton facilities have recently opened or are in planning or construction phases. Furthermore, several companies are actively researching more efficient, * Correspondence