Journal of the Medical Association of Thailand Vol 94, No 3:MARCH 2011 (SUPPL.2) 0125-2208 94 3 2011 Mar A Retrospective Study Comparing Hypofractionated Radiotherapy and Conventional Radiotherapy in Postmastectomy Breast Cancer 94 EN Attapol Pinitpatcharalert Imjai Chitapanarux Juntima Euathrongchit Ekkasit Tharavichitkul Vimol Sukthomya Vicharn Lorvidhaya Original Article From 2004 to 2006, 215 patients were retrospectively reviewed. Sixty seven patients received CRTand 148 patients received HFRT (2.65 Gy in 16-18 fractions). Five-year locoregional control (LRC), disease free survival(DFS), overall survival (OS) and toxicities were analyzed. Median follow-up was 39 months. Five-year LRC was 86.6% in CRT and 85.8% in HFRT (p = 0.852). Five-yearDFS was 62.7% and 69.6% (p = 0.136) in CRT and HFRT, respectively. Patients who received HFRT had significant increasein 5-year OS (62.7% and 73.0% (p = 0.048). No difference of toxicities including changes in chest wall appearance, skinfibrosis, brachial plexopathy, arm edema, pulmonary fibrosis, rib fractures and cardiovascular events was found betweentwo groups. HFRT is as effective as CRT in postmastectomy breast cancer. Breast cancer Hypofractionation Radiotherapy Postmastectomy