ESTRO 2025 - Abstract Book

S1545

Clinical – Mixed sites & palliation

ESTRO 2025

At 3 months follow-up evaluation (primary endpoint) the distribution of pain response in SBRT arm was: complete 88%, partial 0% (i.e.: 88% overall), indeterminate 12%, progression 0%.

Conclusion: SBRT by experimental arm of PREST Trial seems feasible. Toxicity and Pain efficacy must be evaluated at the end of accrual. The preliminary 3 month response rate, (respect the literature standard of 25% complete and 60% overall) will be evaluated for sample size adaptation at interim analysis.

Keywords: SBRT; Pain; Bone Mets

References: REF 1: Cellini f et al; Trials. 2019 Oct 28;20(1):609. doi: 10.1186/s13063-019-3676-x. REF 2: Mizumoto et al; Cancer. 2008 Nov 15;113(10):2816-22. doi: 10.1002/cncr.23888

3083

Digital Poster Toxicity of concurrent biological cancer therapy and stereotactic radiotherapy: a comparison of retrospective and prospective data collection Esmée L Looman 1,2 , Stephanie GC Kroeze 1,2,3 , Mathieu Spaas 4 , Kahl Klaus-Henning 5 , Joost JC Verhoeff 6 , Famke L Schneiders 7 , Oliver Blanck 8 , Fabian Lohaus 9,10,11 , Susanne Rogers 3 , David Kaul 12 , Sergi Benavente 13 , Stephanie E Combs 14 , Georgius Skazikis 15 , Kynann P Aninditha 16 , Ilinca Popp 17 , Friederike LA Koppe 18 , Hans Geinitz 19,20 , Katrien de Jaeger 21 , Shankar Siva 22 , Susanne Stera 23 , Andrea Wittig 24,25 , Victor Lewitzki 25 , Franziska Eckert 26,27 , Markus M Schymalla 28 , Matthias Guckenberger 1,2 1 Radiation Oncology, University Hospital Zurich, Zurich, Switzerland. 2 Faculty of Medicine, University of Zurich, Zurich, Switzerland. 3 Radiation Oncology, Cantonal Hospital Aarau, Aarau, Switzerland. 4 Radiation Oncology, Ghent University Hospital, Ghent, Belgium. 5 Radiation Oncology, Universitätsklinikum Augsburg, Augsburg, Germany. 6 Radiation Oncology, University Medical Center Utrecht, Utrecht, Netherlands. 7 Radiation Oncology, 6Amsterdam UMC location Vrije Universiteit Amsterdam, Amsterdam, Netherlands. 8 Radiation Oncology, University Medical Center Schleswig-Holstein, Kiel, Germany. 9 Radiation Oncology, 8Technische Universität Dresden, Dresden, Germany. 10 Faculty of Medicine, University Hospital Carl Gustav Carus, Dresden University of Technology, Dresden, Germany. 11 Radiation Oncology, University Hospital Carl Gustav Carus, Dresden, Germany. 12 Radiation Oncology, Charité-University Hospital Berlin, Berlin, Germany. 13 Radiation Oncology, Vall d'Hebron University Hospital Campus, Barcelona, Spain. 14 Radiation Oncology, Technical University Munich, Munich, Germany. 15 Radiation Oncology, Schwarzwald-Baar Klinikum, Villingen-Schwenningen, Germany. 16 Radiation Oncology, Klinikum Stuttgart, Stuttgart, Germany. 17 Radiation Oncology, Medical Center - University of Freiburg, Freiburg, Germany. 18 Radiation Oncology, Instituut Verbeeten, Tilburg, Netherlands. 19 Radiation Oncology, Ordensklinikum Linz, Linz, Austria. 20 Faculty of Medicine, Johannes Kepler Universität Linz, Linz, Austria. 21 Radiation Oncology, Catharina Hospital, Eindhoven, Netherlands. 22 Radiation Oncology, Peter MacCallum Cancer Centre and the University of Melbourne, Melbourne, Australia. 23 Radiation Oncology, University Hospital Frankfurt, Frankfurt, Germany. 24 Radiation Oncology, University Hospital Jena, Jena, Germany. 25 Radiation Oncology, University Hospital Würzburg, Würzburg, Germany. 26 Radiation Oncology, University Hospital Tübingen, Tübingen, Germany. 27 Radiation Oncology, University Hospital Zurich, Vienna, Austria. 28 Radiation Oncology, Philipps-University Marburg, Marburg, Germany Purpose/Objective: Metastases-directed stereotactic radiotherapy (SRT) is increasingly performed in (oligo-)metastatic patients treated with immune checkpoint inhibitors (ICIs), monoclonal antibodies, and small-molecule anticancer drugs. However, there is a paucity of data about safety profiles of concurrent treatment with biological cancer therapies (BCT) and SRT 1,2 . We aimed to investigate toxicity of SRT combined with BCT and to compare a retrospective with a prospective multicenter dataset.