D Joseph

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

Background: Intra-operative radiotherapy (IORT) with Intrabeam system has been piloted since 1998 and used in the randomised TARGIT International trial since 2000. Some patients are suitable for off-trial therapy, particularly where external beam radiotherapy (EBRT) cannot be offered due to various reasons. Methods: Patients with invasive breast cancer underwent wide local excision followed by IORT (n=75) 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 breast tissue at the surface of the tumour bed using a spherical applicator (Figure 1). The procedure can be performed in an unmodified operating theatre. Patients who were deemed unfit for surgery received interstitial radiotherapy alone using Intrabeam, with only the point source placed at the tumour centre under stereo-guidance under local anaesthetic, and were followed up with serial MRI scans. Results: Over the past 7 years 78 patients have been treated in this way in centres in 3 countries (UK, Germany and Australia). To date there have been no local recurrences. One patient developed a second primary and subsequently died of brain metastases (Table). Conclusions: This cohort adds to the evidence that targeted radiotherapy using Intrabeam (either IORT or interstitial) could offer a safe and effective method of delivering radiotherapy to breast cancer patients in whom EBRT is not an option. Patients who are suitable for either EBRT or IORT can participate in the TARGIT Trial (Figure 2). Table

5 ORAL A very low recurrence rate is achieved by a targeted intraoperative radiotherapy (TARGIT) boost after breast conserving surgery for cancer

Results: The margin status was clear (>1mm), close (<1mm) and positive in 149/203 (73.3%), 23/203 (11.33%) and 31/203 (15.2%) of the patients. All 54 patients with positive or close margins underwent re-excision or mastectomy and residual tumour was found in 23/54 patients which represent 11.3%(23/203) of the total study (BCT) group. Risk of residual tumour was significant with positive or close margin (P<0.001), large tumour size (P<0.001) and High grade DCIS (P<0.019). Local (Ipsilateral) breast cancer recurrence occurred in 3/203 of patients with a median follow up of 24 months. 2/3 of these patients had High grade DCIS. Conclusion: Our unit policy is supported by the study that BCT with acceptable early local recurrence rate (1% per annum) is achievable with at least 1mm pathological tumour free margin.