Stereotactic radiosurgery for pilocytic astrocytoma: a single center retrospective study

Abstract

Introduction Pilocytic astrocytoma (PA) is a WHO grade I glioma with generally favorable outcomeshowever, 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. Materials and methods 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. Results 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. Discussion and conclusion 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.