# Stereotactic radiosurgery for pilocytic astrocytoma: A single center retrospective study

## TL;DR

This study evaluates the effectiveness of Gamma Knife radiosurgery for treating pilocytic astrocytoma in both children and adults, showing good long-term outcomes.

## Contribution

The study presents one of the largest single-center analyses of Gamma Knife radiosurgery for pilocytic astrocytoma, identifying key predictors of recurrence.

## Key findings

- Gamma Knife radiosurgery provides durable tumor control in both pediatric and adult pilocytic astrocytoma patients.
- Prior radiotherapy is an independent predictor of poorer progression-free survival in both age groups.
- Cystic/mixed tumor morphology increases recurrence risk in pediatric patients.

## Abstract

Pilocytic astrocytoma (PA) is a WHO grade I glioma with generally favorable outcomes; however, deep or eloquent tumor locations often limit safe gross total resection. Gamma Knife radiosurgery (GKRS) has emerged as a minimally invasive alternative for residual or recurrent disease.

A retrospective review of 88 patients (60 diagnosed in childhood and 28 in adulthood) treated with GKRS between 2008 and 2024 was conducted. Clinical, radiological, and treatment parameters were analyzed. PFS was assessed with Kaplan–Meier analysis, and predictive factors were identified using univariate and multivariate Cox regression models.

Median follow-up was 36 months. Pediatric patients showed 5- and 10-year PFS rates of 84.7% and 66.7%, while adults demonstrated 81.7% at both time points. Multivariate analysis identified prior radiotherapy as the only independent predictor of recurrence in the entire cohort, with significant impact also observed in the pediatric subgroup. Cystic/mixed morphology increased recurrence risk in pediatric patients, while no independent predictors were identified in adults.

GKRS provides durable long-term tumor control in both pediatric and adult PA patients. Prior radiotherapy consistently predicts poorer PFS, underscoring its importance in treatment planning. In pediatric patients, tumor morphology also influences outcomes. Despite the retrospective design and cohort heterogeneity, this represents one of the largest single-center GKRS series and supports GKRS as a safe and effective modality for PA management. Prospective studies are needed to refine patient selection and optimize therapeutic strategies.