Quality of Life, Clinical, and Patient-Reported Outcomes after Pencil Beam Scanning Proton Therapy Delivered for Intracranial Grade WHO 1–2 Meningioma in Children and Adolescents

SIMPLE SUMMARY: Meningioma is a rare entity in the pediatric and adolescent population. While maximal resection remains the established standard of care, the role of radiation therapy remains unclear. The aim of this retrospective study was to report the clinical and patient-reported outcomes of a cohort of 10 children and adolescents with intracranial meningioma treated with Pencil Beam Scanning Proton Therapy (PBS-PT) at the Paul Scherrer Institute between 1996 and 2022. The local control rates at three and five years were modest, yet overall survival remained excellent. Some patients reported functional status limitation during first year and 2 years after PBS-PT, with only one reporting limitation after 3 years. The good tolerance of the treatment in terms of acute toxicity and the absence of severe long-term side effects support the safety of the treatment and viability of PBS-PT as a suitable therapeutic option for intracranial meningioma in the pediatric and adolescent population. ABSTRACT: Purpose: The purpose of this study was to report the clinical and patient-reported outcomes of children and adolescents with intracranial meningioma treated with pencil beam scanning proton therapy (PBS-PT). Material and methods: Out of a total cohort of 207 intracranial meningioma patients treated with PBS-PT between 1999 and 2022, 10 (4.8%) were children or adolescents aged < 18 years. Median age was 13.9 years (range, 3.2–17.2). Six (60%) children were treated as primary treatment (postoperative PT, n = 4; exclusive PT, n = 2) and four (40%) at the time of tumor recurrence. Acute and late toxicities were registered according to Common Terminology Criteria of Adverse Events (CTCAE). Quality of life (QoL) before PBS-PT was assessed using PEDQOL questionnaires. Educational, functional, and social aspects after PT were assessed through our in-house developed follow-up surveys. Median follow-up time was 71.1 months (range, 2.5–249.7), and median time to last questionnaire available was 37.6 months (range, 5.75–112.6). Results: Five (50%) children developed local failure (LF) at a median time of 32.4 months (range, 17.7–55.4) after PBS-PT and four (80%) were considered in-field. One patient died of T-cell lymphoma 127.1 months after PBS-PT. Estimated 5-year local control (LC) and overall survival (OS) rates were 19.4% and 100.0%, respectively. Except for one patient who developed a cataract requiring surgery, no grade ≥3 late toxicities were reported. Before PT, patients rated their QoL lower than their parents in most domains. During the first year after PT, one child required educational support, one needed to attend to a special school, one had social problems and another three children required assistance for daily basic activities (DBA). Three years after PT, only one child required assistance for DBA. Conclusions: The outcome of children with intracranial meningioma treated with PBS-PT is in line with other centers who have reported results of radiation therapy delivered to this particular patient group. This therapy provides acceptable functional status profiles with no high-grade adverse radiation-induced events.