Stereotactic arrhythmia radioablation in europe: treatment planning benchmark results of the STOPSTORM consortium

• Published in: Europace (London, England) Vol. 24; no. Supplement_1
• Main Authors: Trojani, V, Botti, A, Grehn, M, Balgobind, B, Savini, A, Pruvot, E, Verhoeff, J, Iori, M, Blanck, O
• Format: Journal Article
• Language: English
• Published: 19.05.2022
• ISSN: 1099-5129; 1532-2092
• DOI: 10.1093/europace/euac053.371

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): EU Background In patients with refractory ventricular tachycardia (VT), STereotactic Arrhythmia Radioablation (STAR) showed promising results for otherwise untreatable patients [1]. The STOPSTORM.eu project coordinates European efforts to clinically validate STAR and to refine protocols and guidelines to ensure treatment harmonization. Purpose The aim of this work is to present the current clinical STAR practise in Europe based on three examples as baseline for further optimization. Methods Target Volumes (TV) and Organs-at-Risk (OAR) were generated from previous consortium benchmarks and consensus definitions for three well-selected STAR cases [1]. Planning Target Volumes (PTV) were generated based on three different compensation strategies for cardiac and respiratory motion [2] and overlapped close OAR like coronary arteries or stomach in some areas. The STOPSTORM.eu members were asked to generate single fraction treatment plans with 25 Gy dose prescription based on ICRU report 91 for each case based on their clinical practise and preferences for STAR including multi-disciplinary discussion and plan approval. Resulting dose distributions were analysed independently using a customized platform for multi-center treatment planning studies [3]. Results Twenty centers submitted 22, 23 and 22 treatment plans for case 1, 2 and 3, respectively, mostly (75% of all plans) using Intensity Modulated Arc Therapy (IMAT) with 6 MeV FFF beams (73% of the IMAT plans) among other commonly used techniques for stereotactic radiotherapy. At this current stage, used guidelines for STAR treatment planning and OAR dose limits vary greatly and are mostly based on the AAPM TG-101 report or the RAVENTA trial publication [4]. As a major finding, 73% of all plans submitted preferred close OAR sparing over achieving high PTV coverage arguing that lower doses down to 20 Gy may also result in clinical efficiency as recently suggested [5]. As a minor finding, 80% of the centers chose to override strong artifact regions originating from e.g. left ventricular assist devices. Conclusion From this first STOPSTORM.eu multi-center multi-platform treatment planning benchmark study we obtained important information concerning current clinical preference and practise from major European centers performing STereotactic Arrhythmia Radioablation for VT. Using the individual and strongly varying approaches of the centers, the key task for the STOPSTORM.eu project is now to find consensus in order to harmonize and optimize STAR practise in Europe.