Simonetta Monti
European Institute of Oncology, Italy
Title: Experience of the European Institute of Oncology in the use of intra-operative radiotherapy with electrons (ELIOT)
Biography
Biography: Simonetta Monti
Abstract
External whole breast radiotherapy (WBRT) is standard treatment after breast-conserving treatment for breast cancer. WBRT markedly reduces recurrence rates and also improves survival. However the RT course lasts 5-7 weeks, and in many countries RT centers cannot meet the demand and may be distant from the patient’s abode. There was therefore much interest in developing intra-operative RT which would complete the RT treatment in a single intra-operative session during surgery. There is also interest in performing only partial irradiation of the tumor bed instead of the whole breast since most recurrences occur close to the scar. In 1999 the European Institute of Oncology (EIO) started a new method of irradiation called ELIOT (intra-operative RT with electrons) which employs a mobile linear accelerator to deliver electrons directly to the reconstructed tumor bed after the surgeon has removed the tumor. The electrons are directed by a Perspex collimator, placed by the surgeon, after a radiation shield has been placed between the breast tissue and the chest wall. The method applies sufficient radiation to the tumor bed, but irradiation to the skin and chest wall is greatly reduced. The aims of this talk are to present the results our ELIOT trial and assess which patients are suitable to ELIOT in the future. The randomized controlled trial to evaluate recruited in 1305 breast cancer patients treated by quadrantectomy and randomized to either conventional external radiotherapy (RT) (654) or ELIOT (651). ELIOT patients received a single dose of 21 Gy to the tumor bed, immediately after quadrantectomy. Patients in the conventional RT arm received 50 Gy in 25 fractions followed by a boost of 10 Gy in 5 fractions. After a median follow-up of 5.7 years, distant metastases and deaths were similar in the two arms, but local relapses (20 cases) in the index quadrant were significantly (p=0.0004) more numerous in the ELIOT than in external RT arm (4 cases). Subsequent analyses found that the excess recurrences in the ELIOT were mainly confined to specific subgroups (those adhering to ASTRO guidelines), allowing indications for ELIOT to be refined. ELIOT appears safe (no difference in survival compared to conventional radiotherapy) and its particular advantage is that it permits definitive surgical and RT treatment for early breast cancer in a single session.