ESTRO 2023 - Abstract Book

S495

Sunday 14 May 2023

ESTRO 2023

26 (30%) and 3 in 10 (11%). The most common histology was colorectal 41 (47%). The primary outcome measure of Grade 3 AEs within 1-year was not modified in the extended follow up. The grade 3 AEs [rate in the MF Arm and SF Arm were 3% [80% CI: 0-10] and 5% [80% CI: 1-13], p = 0.37. There was one grade 5 AE in the MF arm. In the overall cohort, the 3 and 5 year estimates (95% CIs) for OS were 70% (59-78) and 51% (39-61). Overall, the 3 and 5 year estimates (95% CIs) for DFS were 26% (18-36) and 22% (14-32). There were no significant differences between the MF and SF arms for OS (HR 1.1 [95% CI: 0.6-2.1], p = 0.77), or DFS (HR 1.0, [95% CI: 0.6-1.6], p = 0.99; Figure 2). Figure 1: CONSORT Diagram

Figure 2: Efficacy outcomes after SABR comparing each arm

Kaplan-Meier curves illustrating Overall Survival (A) and Disease Free Survival (B).

Conclusion In this patient population, where patients receive SABR in lieu of systemic therapy, SABR is associated with good long term oncological outcomes. Outcomes were similar in the MF and SF SABR arms. Trial Registration: Clinicaltrials.gov ID:NCT01965223 OC-0611 Lungtech EORTC 22113-08113 prospective multicenter trial: SBRT for central lung tumors. S. Adebahr 1,2 , U. Nestle 1,3 , C. Hurkmans 4 , M. Ahmed 5 , S. Ahmad 6 , M. Guckenberger 7 , X. Geets 8 , Y. Lievens 9 , M. Lambrecht 10,11 , N. Pourel 12 , V. Lewitzki 13 , K. Konopa 14 , K. Franks 15 , R. Dziadziuszko 16 , F. McDonald 5 , C. Fortpied 17 , E. Clementel 18 , B. Fournier 18 , H. Rischke 1 , C. Fink 19 , O. Riesterer 7,20 , H. Peulen 21 , A. Grosu 1,2 , C. Faivre-Finn 22 , C. Le Pechoux 23 1 University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Department of Radiation Oncology, Freiburg, Germany; 2 German Cancer Consortium (DKTK), Partner Site Freiburg, Freiburg, Germany; 3 Kliniken Maria Hilf GmbH Mönchengladbach, Department of Radiation Oncology, Mönchengladbach, Germany; 4 Catharina Hospital, Department of Radiation Oncology, Eindhoven, The Netherlands; 5 Royal Marsden NHS Foundation Trust/Institute of