ESTRO 2025 - Abstract Book

S2234

Interdisciplinary – Global health

ESTRO 2025

patients treated between 2012 and 2022 at the Radiation Oncology Department of IEO Evaluate the carbon footprint evolution during a 10-year timespan with a particular focus on the impact of hypofractionated treatments. Keywords: Carbon footprint, Environmental impact, hypofracti

2037

Digital Poster Adaptive radiotherapy in paediatric patients: a SIOP Europe ROWG Survey to map European patterns of practice Andrada Turcas 1 , Stephanie Bolle 2 , Raquel Davila Fajardo 3,4 , Mariangela Fiorente 5 , Sarah M. Kelly 5,6,7 , Yasmin Lassen 8 , Monica Ramos 9 , Enrica Seravalli 10 , Anne Laprie 11 1 Radiotherapy Department, Oncology Institute “Prof. Dr. Ion Chiricuta”, Cluj-Napoca, Romania. 2 Radiotherapy Department, El Centro de Protonterapia Quirónsalud, Madrid, Spain. 3 Department of Radiation Oncology, University Medical Center, Utrecht, Netherlands. 4 Department of Radiation Oncology, Princess Máxima Center for Pediatric Oncology, Utrecht, Netherlands. 5 SIOP Europe, European Society of Paediatric Oncology, Bruxelles, Belgium. 6 Medical Department, EORTC Headquarters, Brussels, Belgium. 7 Faculty of Medicine and Health Sciences, University of Ghent, Ghent, Belgium. 8 Radiotherapy Department, Aarhus University Hospital, Aarhus, Denmark. 9 Department of Radiation Oncology, Vall d'Hebron University Hospital Campus, Barcelona, Spain. 10 Department of Radiation Oncology, Imaging and Oncology Division, University Medical Center Utrecht, Utrecht, Netherlands. 11 Radiation Oncology Department, Oncopole Claudius Regaud, Toulouse, France Purpose/Objective: Adaptive radiotherapy (ART) is an advanced form of delivering radiotherapy which allows for dynamic adjustments of treatment to account for changes in tumoral volume and/or patient anatomy, thus increasing treatment accuracy and potentially improving outcomes as well as reducing toxicities. The use of ART is constantly increasing, including for paediatric patients, despite limited evidence. There are no practice guidelines yet available for adaptive radiotherapy in children and current reports 1,2 indicate a high heterogeneity in practice. This study aimed to map current ART practice for children in radiotherapy departments across Europe. Material/Methods: An online survey was distributed to radiotherapy departments across SIOP-Europe affiliated countries. The survey contained 21 single-choice, multiple-choice and open-ended questions, focused on the implementation of adaptive radiotherapy for paediatric patients. Results: Sixty responses were received from 18 European countries. Most responders (77%) were radiation oncologists, followed by medical physicists (16%). ART was used for both adult and paediatric patients in 71% of the departments, but in half of them, <5% of the children were treated with ART. Anatomical sites for implementation were abdomen (88%), thorax (81%), H&N (81%), and pelvis (74%); with the most frequent tumour types being Nephroblastoma (83%), Neuroblastoma (79%) and Sarcoma (75%) (Figure1). Fifteen percent used ART daily, whereas 75% only when major changes occurred. The most frequent reasons for adaptation were changes in tumour volume/shape (82%), changes in anatomy (74%) and changes in OARs filling/shape (60%). Half of the responders used offline ART, 24% online and 32% both, depending on the situation. Forty-five percent had a specialized treatment unit, such as Ethos (21%), MR-LINAC (5%), or Tomotherapy (13%). Automatic contouring was used in 57% of the cases for OARs and 11.5% for target volumes, while automatic planning or QA was used by 20% and 8.5% of responders, respectively. For a more frequent use of ART, 50% of responders desired more scientific evidence of clinical benefit, specialized equipment (52%), guidelines (39%), time (36%), and manpower (25%) (Figure2).