e11560 Background: To report single-institution series of breast intra-operative radiotherapy (IORT) using nondedicated linear accelerator. Methods: Prospective phaseII trial opened in May 2004. Eligibility criteria: single-focal breast infiltrating ductal carcinoma, age >40 years, size <3cm (after February 2009 >50 years and <2cm) and cN0. Exclusion criteria: carcinoma in situ or lobular types, impossibility of breast-conserving surgery, metastasis or another cancer. Patients underwent classic quadrantectomy with intraoperative margins and SLN evaluation. If both negative, IORT was prescribed (21Gy). Adjuvant treatment considered after definitive pathology report. Endpoints: oncologic, toxicity, aesthetics, and technical issues. Results: From May/2004 to May/2010, 161 patients were enrolled (intention-to-treat analysis) and 34 were excluded. Thus, 127 patients were analyzed. Oncologic analysis involved patients with follow-up ≥24 months (n=83) or breast events. Median age was 56 (40-86) years and median follow-up was 43 (24-72) months. The table summarizes all findings. Conclusions: Single-dose breast IORT presents early oncologic, toxicity, and aesthetic results similar to previously reported trials. Nondedicated facilities have advantages: lower costs; allow higher electron energies; and portal film imaging before treatments. Long-term results will be necessary to strength this data. Summarized results. Parameter Value (%) cT (x, 1, 2) 62.9, 29.9, 7 pT (1,2) 85.8, 14.1 pN (0,1) 86.7, 13.3 Menopausal status (post, pre) 74.5, 25.5 Hormonal receptors (E, P) 84.3, 76 Grade (I, II, III) 33, 24.5, 62.5 Chemotherapy, hormones 15.7, 66.6 3-year survival Overall 97.6 Cause-specific 98.4 Disease-free 96 Recurrences (cumulative) Local 2.4 Loco-regional 1.2 Distant 2.4 Toxicities < 1 month (n) Redness (5), seroma (3),dehiscence (2) ≥ 1 month (n) Fat necrosis (10), fibrosis (20),lymphedema (2), and papillaretraction (3) One-year aesthetic evaluation (RTOG/NSABP score)(excellent, good, regular, bad) 91.7, 4.5, 1.8, 0.9 Electron energies (6, 9, 12, 15, 18 MeV) 7.8, 51.5, 35.1, 3.9, 0.7 Shield repositioning (no, yes) 70.3, 29.7 In-hospital infections None