Outcomes Following Proton Radiation for Pediatric Meningiomas

BACKGROUND: Pediatric meningiomas make up 2% of all pediatric central nervous system tumors and are distinct from adult meningiomas, often coinciding with neurofibromatosis-2 (NF2). However, there is limited useful outcome data regarding pediatric meningiomas treated with radiation therapy (RT).

PROCEDURES: We identified 18 pediatric patients with meningiomas treated at our institution between 2006 and 2024 with proton therapy (PT). All patients received a total dose of 50.4-59.4 Gy in 1.8 Gy/fraction daily, based on tumor grade. Nine patients had WHO Grade I meningiomas and nine had WHO Grade II meningiomas. Sixteen of 18 patients had gross disease at the time of RT. The male-to-female ratio was 1:1. Seven of 18 patients had an NF2 diagnosis. Kaplan-Meier statistical analysis was employed to estimate progression-free survival (PFS), local recurrence, and overall survival (OS) rates. We assessed toxicity during on-treatment visits and follow-ups based on severity and need for intervention.

RESULTS: Median follow-up was 8.5 years (range: 0.5-18 years). No patients were lost to follow-up. At 10 years, local control was 87%, PFS was 75%, and OS was 94%. One patient died from a radiation-associated second neoplasm, and one died from cerebral vasculopathy occurring in the high-dose region. Other notable radiation-related toxicities included hearing loss (n = 1), cataract formation (n = 1), and endocrinopathy (n = 2). No patients had progressive vision loss.

CONCLUSION: This study contributes to the limited data for children with meningioma requiring RT. Long-Term disease control was encouraging and aligned with adult meningioma data. Despite the use of PT, serious radiation toxicity was observed.