ID #1033 Impact of novel strategies in children diagnosed with DIPG

Abstract Introduction Diffuse intrinsic pontine gliomas (DIPGs) are a subset of diffuse midline gliomas (DMGs) with poor prognosis. Median overall survival (OS) is estimated to be less than 12 months, with approximately 90% of patients dying within two years of diagnosis. Advances in the diagnosis and treatment of pediatric brain tumors have expanded our understanding of DIPGs, creating opportunities to develop novel therapeutic strategies for these patients. We aim to analyze the DIPG case series diagnosed over the past 25 years at a Pediatric Neuro-oncology Unit in a tertiary center in Spain to evaluate the different strategies used and their impact on the outcome. Methods Retrospective series of DIPG patients diagnosed at the Niño Jesús Childreńs Hospital between January 2000 and December 2025. Clinical, radiological, histopathological, molecular, and survival data were collected. Survival outcomes were calculated using the Kaplan-Meier and univariable Cox proportional hazards methods. Results 27 patients were identified. Median age was 8.5 years (range 3.1–18.7).16/27 (59.3%) were female. Clinical trial enrollment was documented in 14/27 (51.9%). Biopsy was performed in 16/27 (59.3%). Re-irradiation was recorded in 15/27 (55.6%). The median OS was 11.7 months (IC95% 10.4-16.4 months). Re-irradiation was associated with longer survival (HR = 0.24, 95% CI 0.06–0.90; p = 0.034). However, the inclusion in clinical trials and biopsy were not associated with better outcomes, with a HR = 1.30, 95% CI 0.57–2.96 (p = 0.53) and HR = 0.78, 95% CI 0.34–1.79 (p = 0.56) respectively. Conclusion Prognosis in DIPG remains poor. Reirradiation was the only strategy associated with prolonged survival in our series. Although participation in clinical trials did not lead to improved survival outcomes, it enabled patients to access novel therapies and contributed to safety assessments, providing preliminary evidence to support future studies in this devastating disease.