ESTRO 2021 Abstract Book

S1169

ESTRO 2021

Conclusion Peri-operative brachytherapy is feasible and well-tolerated and allows a moderate dose-escalation in patients with soft-tissue sarcomas. Furtherer studies are needed to find out dose-escalation benefits in pathological response, local control, and definitely survivals. PO-1423 Preoperative radiotherapy and concurrent chemotherapy in advanced soft tissue sarcomas. A.M. Burgueño Caballero 1 , Ó. Muñoz Muñoz 1 , J. Peinado Serrano 1 , I. Rincón Pérez 2 1 Hospital Universitario Virgen del Rocío, Radiation Oncology, Sevilla, Spain; 2 Hospital Universitario Virgen del Rocío, Radiation Oncologý, Sevilla, Spain Purpose or Objective This retrospective study evaluated at the tolerability and outcomes of preoperative radiotherapy (P-RT) with concurrent chemotherapy (CT) for patients with advanced soft tissue sarcomas (ASTS). Materials and Methods Between January/2016 and November/2020, 38 patients (male/female 27/11) with ASTS, were treated with P- RT (50Gy in 25 Fractions) with concurrent CT (3 cycles): Epirubicin + ifosfamide; Antitumor activity was assessed by preoperative-RMN by RECIST, modified Choi criteria and pathological response. Surgical specimens were processed for histologic changes and rate of residual visible tumor. Results The median age of 54 years (range 19-86). In term of histology, 28,9% were GII and 71,1% GIII. Patients were treated in 3D/IMRT 8/30. GTV: defined MRI; CTV: GTV +2,5cm. Patients received 50 Gy in 25 fractions at 5/week, with 3 cycles of Epirubicin 60mg/m2/d d1-2 + Ifosfamide 3g/m2/d d1-3 each 3 weeks. 65% patients had no acute Radiodermitis G>3. No dose-reductions or interruptions (>2 days) were registered. All patients completed RT, and 28 were evaluated for response. By RECIST: 10 achieved PR (35,7%), 13 SD (46,5%), 5 PD (17,8%). By Choi: 17 achieved PR (60,7%), 9 SD (32,1%), 2 PD (7,2%).