ESTRO 2022 - Abstract Book

S1022

Abstract book

ESTRO 2022

due to societal and social stigmata or due to financial constraints that restrict access to reproductive health services for many women in developing countries. Another possible explanation could be the effects of tamoxifen on endometrium and the lower reproductive tract. Though we used resumption of menstrual cycle as an indirect measure of endometrial health and there was some delay in resumption of menstruation in patients on tamoxifen therapy, this ratio did not reach statistical significance.

PO-1202 Intraoperative radiation therapy in second conservative surgeries for early breast cancer

A. Lanuza Carnicer 1 , C. Escuin Troncho 1 , M. Cerrolaza Pascual 1 , V. Navarro Aznar 1 , J. Díaz Abad 1 , A. Campos Bonel 1 , M.P. Sanagustín Piedrafita 1 , J.M. Ponce Ortega 1 , F.J. Villalobos Salguero 2 , A. Palomares Cano 3 , V. Rodrigo Vinue 3 , C. García Aguilera 1 , M.R. Ibáñez Carreras 1 1 Hospital Universitario Miguel Servet, Radiation Oncology, Zaragoza, Spain; 2 Hospital Universitario Miguel Servet, Gynecology and Obstetrics, Zaragoza, Spain; 3 Hospital Universitario Miguel Servet, General Surgery and Digestive System, Zaragoza, Spain Purpose or Objective Mastectomy is the current standard treatment for recurrence of breast cancer (BC) or second tumors after previous glandular irradiation. Breast-conserving surgery (BCS) with reirradiation by intraoperative radiation therapy (IORT) in the ipsilateral breast is an emerging technique in the treatment of early stage cases. Materials and Methods 711 patients with BC treated by IORT between may 2015 and septembrer 2021 were retrospectively analyzed. Those with a previous history of ipsilateral BC who underwent a second BCS and IOR were selected. A total of 20 Gy was administered with Axxent Xoft device during surgery. Different variables such as pathological and radiological features, toxicities according to the CTCAE scale (v.5) and local control were studied. Results Of the total, 9 patients (1.27%) met the established selection criteria. The initial treatment in 8 patients was BCS and external radiotherapy (EBRT) and in 1 BCS and IORT. In the second BCS, IORT was administered to all patients. Mean time between both surgeries was 12 years. In 3/9 cases (33.3%) the recurrence took place in the same quadrant. 100% were invasive ductal carcinoma (IDC): 8 Luminal A (88.8%) and 1 triple negative (TN) wich was out of protocol due to the patient’s refusal to mastectomy. The mean size was 11,4mm. In the ultrasound control one month after the surgery, seroma was observed in 5 patients and glandular edema in 3 patients. Regarding to dermatological toxicity, 2 patients developed acute G1 radiodermatitis and only 1 patient developed chronic toxicity, that was resolved 6 months later. None of the Luminal profile tumors recurred after a median follow-up of 23.6 months. Conclusion For those pacients with recurrent breast cancer in the ipsilateral breast after previous glandular radiotherapy, second breast-conserving surgery with IORT is a feasible treatment with excellent tolerance in selected cases with a favorable prognosis profile. V. Navarro Aznar 1 , A. Campos Bonel 2 , C. Escuín Troncho 2 , A. Miranda 3 , M. Cerrolaza Pascual 2 , A. Lanuza Carnicer 2 , S. Flamarique Andueza 2 , P. Rubio 4 , V. Alba Villalba 5 , M.C. Casamayor Franco 6 , R. Ibáñez Carreras 2 1 Hospital Universitario Miguel Servet, Radiation Oncology , Zaragoza, Spain; 2 Hospital Universitario Miguel Servet, Radiation Oncology, Zaragoza, Spain; 3 SOLCA Matriz Guayaquil , Radiation Oncology, Guayaquil, Ecuador; 4 Hospital Universitario Miguel Servet, Gynecology, Zaragoza, Spain; 5 Hospital Universitario Miguel Servet, Radiophysics, Zaragoza, Spain; 6 Hospital Universitario Miguel Servet, General Surgery, Zaragoza, Spain Purpose or Objective Intraoperative radiotherapy (IORT) can be used as a technique of tumour bed overimpression in patients with molecular profile early stage high-risk breast cancer (Her2+ and Triple Negative) in whom initial surgical treatment is performed. This technique is considered an option for local treatment until completion of external radiotherapy, once systemic therapy has been completed, with an impact on local control of the disease. Our objective is to analyse local control and toxicity. Materials and Methods From a total of 707 patients treated between May 2015 and May 2021 with IORT in our community, 31 patients received initial treatment as boost, delivering a single dose of 20Gy using 50 kV X-rays. Subsequently, this was completed with hypofractionated hologlandular external beam radiotherapy. We analysed demographic, surgical, radiotherapeutic and local control data. Results The mean age was 67 years. All tumours were infiltrating ductal carcinoma with a mean size of 14.53mm. 77.42% (n=24) were Triple Negative, 19.35% (n=6) Luminal B-HER2+ and 3.22% (n=1) pure Her2. PO-1203 Targeted Intraoperative Radiotherapy Tumour Bed Boost: Our experience