ESTRO 2025 - Abstract Book

S1632

Clinical – äediatric tumours

ESTRO 2025

Conclusion: The study revealed critical gaps in AYA radiotherapy care, even within a leading center like Gustave Roussy. Recommendations include staff training, improved infrastructure, enhanced interdepartmental communication, and tailored patient support systems. Proposed improvements involve dedicated AYA consultation spaces, adaptable digital tools, structured care pathways, and increased integration of radiotherapy teams with AYA units. These changes aim to provide holistic and effective care tailored to AYA patients, fostering better outcomes and patient satisfaction.

Keywords: AYA, Radiotherapy, care

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Mini-Oral Late adverse effects of proton radiation for pediatric low grade gliomas Noura Sellami 1 , valentine martin 1 , jacques Grill 2 , stephanie bolle 1 1 radiation therapy, Gustave Roussy, villejuif, France. 2 pediatric oncology, Gustave Roussy, villejuif, France Purpose/Objective: Pediatric patients with low -grade gliomas (LGG) have a long survival but risk incurring late adverse effects from standard photon based radiation therapy. Proton radiotherapy offers better dose conformity and potentially reduces the risk of radiation related toxicity. We examined long-term morbidity following proton therapy in this cohort of patients with LGG. Material/Methods: Forty-six pediatric patients with LGGs of the brain were treated with protons from 1991 to 2021. Comprehensive baseline and longitudinal assessments of late toxicity (pseudoprogression, visual and endocrine outcomes, ototoxicity, neurocognition, vasculopathy and second cancers) were analyzed. Results: The median age at diagnosis was 7 years (3 months-17 years). Most patients were biopsied (73.2%), with a diagnosis of pilocytic astrocytoma in 54.3%. The lesions were supratentorial in 65.21%. Partial resection was performed in 28 patients and 55.2% of the patients received systemic treatment before starting proton therapy. The median age at proton therapy was 11.5 years (3 – 20 years) with a median radiation dose of 54 GyE (50.2 GyE – 54 GyE). At a median follow-up of 8.5 years (18 months-260 months), overall survival (OS) and progression-free survival (PFS) at 10 years were 97.5% and 78%, respectively. The local control rate was 80,4%. Pseudo progression was diagnosed in seven patients (15,2%) during the first year of follow-up, two patients kept neurological sequelae after this. An improvement of visual acuity was achieved in six patients. Degradation of vision unrelated to tumor progression was observed in one patient. Only one patient had Grade 2 hearing loss 36 months after the end of proton therapy. An endocrinopathy was found in nine patients. The somatotropic axis was the first affected. Nine patients reported neurocognitive symptoms after radiation: five patients with Grade 1 and four patients with Grade 2. Only one patient presented a symptomatic vasculopathy 14 years after the end of proton therapy. No second cancer was documented. Conclusion: Proton therapy is associated with good clinical outcomes. Depending on the tumor location, it can spare dose to some critical organs and his is directly correlated with fewer complications. Its indication should be discussed early in the course of management of certain well-selected patients.

Keywords: low-grade glioma, proton therapy, late effects