ESTRO 2020 Abstract Book

S40 ESTRO 2020

Individualized dose constraints were used for bone and skin corridor. An intraoperative radiation therapy (IORT) boost was planned for expected close or positive surgical margins. Results Between August 2006 and January 2019, 147 pts ( M/F:89 /58), median age: 65 yrs (20-89) with extremity (122pts) and superficial trunk (25pts) underwent to RT with 40.5Gy/18frs. Pts with primary disease were 111(75,5%) and 36 pts (24,5%) had recurrent disease. Most common histologic types were LipoSa (35,3%), PleomorphicSa (17%), LeiomyoSa 17(11%) and MixofibroSa (8%). Overall, 50 pts (34%) had G1, 41( 28%) G2 and 56 pts (38%) had G3 disease. All but 3 pts completed the planned 40.5 Gy. At surgery, 115 pts (78%) had R0 resection and 32 pts (22%) R1 resesction; 94 pts ( 64%) underwent IORT for close or positive margins at surgery. Only 5 pts (3,4%) had G3 acute skin toxicity. Major postoperative complications ( SR2 criteria) were reported in 19/147 pts (13%). At a median follow up of 33 months ( range 9-108 ) the DFS and OS at 2 and 5 years were 82% and 68%, and 87,4% and 71,4% , respectively. The cumulative incidence of local recurrence (LR) and distant metastases at 5 years were 13% and 26% respectively. No significant difference in LR were reported in IORT and no-IORT pt subgroup ( Long Rank p=0,4) Conclusion Preoperative moderate Hypofractionation RT with 40.5Gy/18 frs, 2.25 Gy/ fr for Extremity and superficial trunk STS appears safe and feasible with favourable oncologic outcomes. Dose escalation with IORT is feasible, when need. This results provide an available evidence, well comparable with standard dose and fractionation, and could be useful for further investigations OC-0088 Neoadjuvant Radiotherapy vs Chemoradiotherapy for High-Risk Extremity and Trunk Soft Tissue Sarcoma M. Chowdhary 1 , A. Chowdhary 2 , N. Sen 1 , N. Zaorsky 3 , K. Patel 4 , D. Wang 1 1 Rush University Medical Center, Radiation Oncology, Chicago, USA ; 2 Robert H. Lurie Comprehensive Cancer Center- Northwestern University, Hematology and Medical Oncology, Chicago, USA ; 3 Penn State Cancer Institute, Radiation Oncology, Hershey, USA ; 4 Yale School of Medicine, Therapeutic Radiology, New Havent, USA Purpose or Objective Patients with large, high-grade extremity and trunk (ET) soft-tissue sarcomas (STS) are at high risk for distant recurrence and death. The integration of chemotherapy (C) to standard of care neoadjuvant radiotherapy (RT) remains controversial even for these patients due to conflicting trial results and toxicity concerns. This study examines the impact of adding C to neoadjuvant RT on overall survival (OS) in high risk ET-STS. Material and Methods The National Cancer Data Base (NCDB) was queried for patients ≥18 years with high risk (≥5 cm + FNCLCC grade 2- 3) ET-STS (histology per NRG DT001) who received neoadjuvant RT and limb sparing surgery from 2006-2014. Patients were stratified based upon receipt of C (RT and CRT cohorts). Overall survival (OS) for RT vs CRT cohorts was analyzed using the Kaplan-Meier (KM) method, log-rank test & Cox proportional hazards models. Propensity score-matched analysis (PSM) was employed to account for potential treatment selection bias between cohorts. Mean inpatient stay, 30-day unplanned readmission rate and 90-day mortality were calculated as surrogates for toxicity. Results A total of 884 patients were identified: 639 (72.3%) in the RT cohort & 245 (27.7%) in the CRT cohort.

Conclusion A hypoxia signature nanoString® assay with excellent technical performance is prognostic in two independent cohorts of patients with high-grade tumours, including the phase III VorteX radiotherapy trial. The assay could identify high-risk patients for adjuvant chemotherapy trials. OC-0087 Preoperative Hypofractionated Radiation Therapy for Soft Tissue Sarcomas of Extremity and Trunk F. Navarria 1 , A. Lauretta 2 , E. Palazzari 1 , R. Innocente 1 , M. Gigante 1 , A. Caroli 1 , V. Canzonieri 3 , A. Buonadonna 4 , F. Gherlinzoni 5 , J. Polesel 6 , G. Bertola 2 , A. De Paoli 1 1 Centro di Riferimento Oncologico di Aviano IRCCS, Radiation Oncology, Aviano, Italy ; 2 Centro di Riferimento Oncologico di Aviano IRCCS, Surgical Oncology, Aviano, Italy ; 3 Centro di Riferiemnto Oncologico di Aviano IRCCS, Pathology, Aviano, Italy ; 4 Centro di Riferimento Oncologico di Aviano IRCCS, Medical Oncology, Aviano, Italy ; 5 Ospedale di Gorizia- Monfalcone, Orthopedic, Gorizia, Italy ; 6 Centro di Riferimento Oncologico di Aviano IRCCS, Cancer Epidemiology, Aviano, Italy Purpose or Objective Radiation Therapy (RT) and Conservative Surgery (S) is a well established approach in most part of extremity and superficial trunk soft tissue sarcomas (STS). Preoperative RT, with a dose of 50Gy/25 fractions (frs), 2Gy fr, is the emerging option as preferred option, compared to postoperative RT, for better long-term anatomic and functional results. Hypofractionated RT represent an increasingly interest in STS. We evaluated feasibility and oncologic outcomes of preoperative moderate hypofractionated RT in this setting of STS patients (pts) treated at our Institute. Material and Methods A retrospective analysis of cohort of consecutive pts was performed. Pts selection included no high-risk pts candidate to (neo)adjuvant chemotherapy and no critical tumor sites. Advanced RT techniques such as 3D-CRT and IMRT-IGRT were used. A moderate hypofractionation of RT dose of 40.5Gy/18frs, 2,25Gy/fr, was planned.