The Role of Reirradiation in Childhood Progressive Diffuse Intrinsic Pontine Glioma (DIPG): An Ongoing Challenge beyond Radiobiology.

To investigate the clinical impact of multiple courses of irradiation on pediatric patients with progressive diffuse intrinsic pontine glioma (DIPG), we conducted a retrospective case series on three children treated at our institution from 2018 to 2022. All children were candidates to receive systemic therapy with vinorelbine and nimotuzumab. Radiotherapy was administered to a total dose of 54 Gy. At any disease progression, our local tumor board evaluated the possibility of offering a new course of radiotherapy. To determine feasibility and assess toxicity rates, all children underwent clinical and hematological evaluation both during and after the treatment. To assess efficacy, all children performed contrast-enhanced MRI almost quarterly after the end of the treatment. In all children, following any treatment course, neurological improvement (>80%) was associated with a radiological response (41.7-46%). The longest overall survival (24 months) was observed in the child who underwent three courses of radiotherapy, without experiencing significant side effects. Even though it goes beyond the understanding of conventional radiobiology, first and second reirradiation in pediatric patients with progressive DIPG may represent a feasible and safe approach, capable of increasing overall survival and disease-free survival in selected patients and improving their quality of life.