Gamma Knife Stereotactic Radiosurgery for Pediatric Meningiomas

Despite the generally benign and slow-growing nature of many adult meningiomas, meningiomas in pediatric patients often exhibit more aggressive behavior. Gamma Knife stereotactic radiosurgery (SRS) is a non-invasive modality that is widely used as either an initial upfront or adjuvant management for meningiomas. We reviewed our 35-year meningioma experience to assess its role in pediatric patients.

The authors reviewed the clinical and imaging data of 2,030 meningioma patients who underwent SRS between 1987 and 2022 at the University of Pittsburgh Medical Center (UPMC). We identified 9 patients <18 years (2 female; median age, 14.5 years). None of the patients had neurofibromatosis type 2. The neurological outcomes, overall survival, local tumor control, and development of adverse radiation effects were evaluated. Three patients received prior therapeutic radiation: one underwent prophylactic cranial irradiation for lymphoblastic leukemia, one received focal cranial irradiation for craniopharyngioma, and one underwent craniospinal irradiation for medulloblastoma. Seven patients had prior tumor resection, while two asymptomatic patients were diagnosed incidentally (one during craniopharyngioma surveillance imaging and the other after head trauma). The median cumulative tumor volume at SRS was 6.0 cc (range, 0.5-11.8 cc). The median margin dose prescribed was 14 Gy (range, 11-25 Gy).

At last follow-up, 5 patients were alive. Four patients had died, two from progressive intracranial disease and two from unrelated medical causes. The median overall survival was 8.9 years (range 2.0-16.2 years). The median progression free survival was 8.2 years (range 1.1-13.4 years). Five patients experienced tumor progression at a median of 2.1 years (range, 1.1-13.4 years) after SRS. After local tumor progression, 2 patients received repeat SRS, and the remaining patients required additional surgery, fractionated external beam radiotherapy, or chemotherapy. No patient developed adverse radiation effects, had malignant tumor transformation, or developed other types of CNS malignancies.

Meningiomas are rare tumors in the pediatric age group and can exhibit aggressive behavior. Tumor control was achieved in 6 of 9 patients after one or more SRS procedures. SRS presents as a reasonable primary option or should be considered for early intervention after surgery. Patients and families should be counseled that multiple SRS sessions might be needed to achieve eventual tumor control.