S1000
Clinical – Paediatric tumours
ESTRO 2026
Conclusion: In this pediatric ependymoma cohort, no grade ≥ 3 RIBI was observed. The incidence of brain injury was 29.2% (grade 1: 25.0%; grade 2: 4.2%), and the incidence of brainstem injury was 16.7% (all grade 1). While predictive modelling was not feasible due to small sample size and event rarity, exploratory evidence indicates that intermediate-dose brain volumes (V30, V50) may influence injury risk. Clinically, preferential reduction of V30/V50 may be reasonable when comparing otherwise equivalent plans. Validation in larger multi-institutional datasets is needed to confirm these findings and develop robust predictive tools. References: 1. Common Terminology Criteria for Adverse Events (CTCAE) v5.0. U.S. Department of Health and Human Services, National Cancer Institute; 2017.2. Bentzen SM, Constine LS, Deasy JO, Eisbruch A, Jackson A, Marks LB, et al. Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC): An introduction to the scientific issues. _Int J Radiat Oncol Biol Phys_. 2010;76(3 Suppl):S3–9. Keywords: ependymoma, proton therapy, brain injury Two decades of insight: key findings from a French retrospective multicenter analysis of pediatric localized intracranial ependymoma (NCT05151718) Fatima TENSAOUTI 1 , Alexis Marguerit 2 , Mathilde Morisseau 3 , Stéphanie Bolle 4 , Audrey Jorand 5 , Xavier Muracciole 6 , Claire Alapetite 7 , Line Claude 8 , Julie Leseur 9 , Aymeri Huchet 10 , Jérôme Doyen 11 , Claire Dossun 12 , Stéphane Supiot 13 , William Gehin 14 , Dominique Figarella-Branger 15,16 , Pascale Varlet 17 , Aurore Siegfried 18,19 , Julien Gautier 20 , Pierre Leblond 21 , Anne Laprie 1 1 Radiation oncology, Univ Toulouse, Oncopole Claudius Regaud, IUCT-Oncopole, Inserm, ToNIC, Toulouse, France. 2 Radiation oncology, Institut du Cancer de Montpellier, Montpellier, France. 3 Biostatistics & Health Data Science Unit, Oncopôle Claudius Regaud, Institut Universitaire du Cancer de Toulouse, Toulouse, France. 4 Radiation oncology, Institut Gustave Roussy, Paris, France. 5 Radiation Proffered Paper 821 oncology, Centre Oscar Lambret, Lille, France. 6 Radiation oncology, CHU La Timone, Marseille, France. 7 Radiation oncology, Institut Curie, Paris, France. 8 Radiation oncology, Centre Léon Bérard, Lyon, France. 9 Radiation oncology, Centre Eugène Marquis, Rennes, France. 10 Radiation oncology, CHU Bordeaux, Bordeaux, France. 11 Radiation oncology, Centre Antoine-Lacassagne, University of Côte d’Azur, Nice, France. 12 Radiation oncology, ICANS, Strasbourg, France. 13 Radiation oncology, Institut de cancérologie de l’ouest, Nantes, France. 14 Radiation oncology,
threshold (Figure 1). No stable predictors emerged for brainstem. In multivariable analysis, neither clinical nor DVH factors reached statistical significance (all p>0.20). An in-sample model with V30 and V50 achieved ROC AUC 0.71 but lacked generalizability. Figure 2 illustrates injury distribution by V30 and V50.
Made with FlippingBook - Share PDF online