Intraoperative radiotherapy during breast conserving surgery : a study on 1,822 cases treated with electrons

Intraoperative radiotherapy with electrons (ELIOT) after conservative surgery for breast carcinoma was introduced at the IEO in 1999 as a research programme. The results on 1,822 patients treated from January 2000 to December 2008 are reported. Women with unicentric primary breast carcinoma of less than 2.5 cm in the largest diameter were assessed by imaging. All patients were treated with breast-conserving surgery (quadrantectomy). ELIOT was delivered by two mobile linear accelerators immediately after breast resection with a single dose of 21 Gy. Local side effects of ELIOT were mainly liponecrosis (4.2%) and fibrosis (1.8%). After a mean follow-up of 36.1 months, 42 women (2.3%) developed a local recurrence, 24 (1.3%) a new primary ipsilateral carcinomas and 26 (1.4%) distant metastases as first event. Forty-six women died (2.5%), 28 for breast carcinoma and 18 for other causes. Five- and ten-year survivals were, respectively, 97.4 and 89.7%. ELIOT appears a promising feature in early breast cancer treated with breast conserving surgery, reducing the exposure of normal tissues to radiations and shortening the radiation course from 6 weeks to one single session.