Breast cancer patients treated with intra-operative radiotherapy [IORT] alone when conventional external beam radiation therapy [EBRT] was not possible

11517 Background: IORT with Intrabeam has been used by us in the randomised TARGIT trial since 2000. Some patients are suitable for off-trial therapy, particularly where external beam radiotherapy cannot be offered due to the risk of side effects. Methods: Patients with invasive breast cancer underwent wide local excision followed by IORT (n=14) delivered using the Intrabeam system containing a miniature electron gun and accelerator. Low energy x-rays (50kV) are emitted from the point source, delivering 20Gy to the applicator surface located in the tumour bed. Patients who were deemed unfit for surgery (n=3) received interstitial radiotherapy alone using Intrabeam under local anaesthetic without any surgical intervention and were followed up with serial contrast enhanced MRI scans. Results: The median (IQR) age of these 17 patients at the time of IORT was 68 (56–78) years with a median (IQR) follow-up of 21 (13- 43) months (see Table). To date there have been no reports of local recurrence or radiation in...