Full-dose intraoperative radiotherapy with electrons during breast-conserving surgery : experience with 590 cases

BACKGROUND: Previous studies show that local recurrences after breast-conserving treatment occur in the site of the primary tumor. The need for postoperative radiotherapy on the whole breast is challenged in favor of radiotherapy limited to the area of the breast at high risk of recurrence. The new mobile linear accelerators easily moved close to the operating table to allow the full-dose irradiation during surgery. PATIENTS AND METHODS: From July 1999 to December 2003, 590 patients affected by unifocal breast carcinoma up to a diameter of 2.5 cm received wide resection of the breast followed by intraoperative radiotherapy with electrons (ELIOT). Most patients received 21 Gy intraoperatively, biologically equivalent to 58 to 60 Gy in standard fractionation. Patients were evaluated 1, 3, 6, and 12 months after surgery, and thereafter every 6 months, to look for early, intermediate, late complications, and other events. RESULTS: After a follow-up from 4 to 57 months (mean, 24 months; median, 20 months), 19 patients (3.2%) developed breast fibrosis, mild in 18, severe in 1, which resolved within 24 months. Three patients (0.5%) developed local recurrences, 3 patients ipsilateral carcinomas in other quadrants and other 5 patients contralateral breast carcinoma. One patient (0.2%) died of distant metastases. CONCLUSIONS: ELIOT is a safe method for treating conservatively operated breasts, avoids the long period of postoperative radiotherapy, and reduces drastically the cost of radiotherapy. ELIOT reduces radiation to normal tissues and organs. Results on short-term and middle-term toxicity up to 5 years of follow-up are good. Data on local control are encouraging.