[Firs Case Report of Intraoperative Radiotherapy (IORT) for Early Breast Cancer in Bulgaria].

The intraoperative radiotherapy (IORT) is an innovative method for treatment of breast cancer, which can be used as a substitute of postoperative external beam radiotherapy )EBRT), or boost treatment to EBRT (1). Radiobiological advantages of IORT compared to EBRT are higher relative biologic effectiveness of low-dose radiation therapy and the presence of high dose in the tumor bed (where the possibility of remaining vital tumor cells is the highest), as this dose reduces rapidly with the distance from the applicator (2). Important feature of IORT alone is that it can be applied as a single fraction during the surgical intervention and spares 3 to 5 weeks of following radiation therapy. This means less time spent in hospital for the patients and for the radiotherapeutical units - reduced waiting lists and more machine time for other patients. Prolonged operative time as well as the need of additional staff are assumed as relative flaws of IORT (3). The INTRABEAM® system (Carl Zeiss Surgical Gmbh, Oberkochen, Germany) uses a single high dose of low-energy X-rays (mas 50kV), applied to the tumor bed immediately after the surgical excision of the tumor. These rays have high degree of absorption and low penetrating ability. This determines their advantage in comparison to EBRT to protect the surrounding healthy tissues (2). The data from the Targeted Intraoperative radioTherapy (TARGIT-A) and the Intraoperative radiotherapy versus external radiotherapy for early breast cancer (ELIOT): a randomized controlled equivalence trial show that when following the recommendations of The Groupe Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology (GEC-ESTRO) Breast Cancer Working Group (2009) for an accelerated partial breast irradiation (APBI), IORT can be used as an equivalent of the postoperative radiotherapy (1,4,5,6). The purpose of this article is to show the results of the performed on 15 December 2015 for the first time in Bulgaria breast conserving surgery with intraoperative radiotherapy on a patient with early breast cancer.