Proton-Based Re-Irradiation of Locally Recurrent Pediatric Brain Tumors in Close Proximity to the Brainstem
Year: 2025
Type: article
Abstract: Purpose Local recurrence of aggressive, pediatric brain tumors remains a challenge. We offered full-course re-irradiation with proton therapy (PT) to children with local failures in proximity to the brainstem. Patients and Methods Eleven children (7 male, 4 female) underwent fractionated re-irradiation using pencil beam-based PT for local recurrence following maximum prior multidisciplinary treatment, for ependymoma (N=6), atypical teratoid rhabdoid tumor (N=3), papillary tumour of pineal region (N=1) and atypical meningioma (N=1). Median age at first radiotherapy (RT) was 4.5 years (range: 1.5-14.8); at re-RT was 6.7 years (range: 3.0-18.9); median interval between courses was 21 months (range: 13-160). In 9/11 children Gross Tumor was identifiable. Primary RT was with photons (N=6) or protons (N=5). Re-RT planning was based on cumulative dose summation. Permissible re-RT OAR doses were individualized. Median prescription dose was 54.0 Gy(RBE) (range 44.0-54.0). All re-treatments were delivered at 1.8-2.2 Gy(RBE) per fraction. A constant RBE value of 1.1 was used. Results At median follow up of 42.5 months (range 7-63), 9 /11 children (82%) achieved local control. Actuarial 2- and 3-year local control and overall survival rates were 89% and 76%, and 82% and 73%, respectively. Strategies of balancing target dose with OAR considerations resulted in a median cumulative brainstem surface dose (D 0.1cc) of 81.5 Gy(RBE) (range: 65.8-99.48). No CNS toxicities ≥ Grade 2 were observed, specifically no symptomatic brainstem or brain necrosis. Conclusion Selective re-irradiation with pencil beam-based proton radiotherapy, using specifically modified treatment planning approaches, can be effective and safe, even in cases with tumor abutting the brainstem.
Language: English
Subfield: Pulmonary and Respiratory Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $1,700
OpenAlex ID: W4416745995