Stereotactic radiosurgery for subependymal giant cell astrocytoma: multi-institutional retrospective analysis of clinical and radiological outcomes

Abstract

OBJECTIVE: Subependymal giant cell astrocytomas (SEGAs) are benign tumors linked to tuberous sclerosis complex. Surgical resection remains the primary treatment, but carries risks of morbidity, particularly in cases of residual or recurrent disease. Stereotactic radiosurgery (SRS) offers a minimally invasive alternative, though evidence of its efficacy is unclear. This study presents a retrospective, multi-institutional analysis of SEGA outcomes after SRS. METHODS: Fourteen patients with histologically confirmed SEGA underwent Gamma Knife radiosurgery between 1998 and 2023 across seven centers of the International Radiosurgery Research Foundation. Demographics, tumor features, treatment parameters, and outcomes were evaluated. Local control (LC), progression-free survival (PFS), overall survival (OS), quality of life, and toxicity were analyzed. RESULTS: The median age at treatment was 17 years, and all patients had prior surgery. Median radiological and clinical follow-up were 75 and 77.8 months. LC was achieved in 57.1% of cases, while 42.9% showed local failure, including one distant progression. PFS rates were 85.7% at 12 months and 71.4% at 24 months, with corresponding OS rates of 92.9% and 85.7%. No significant predictors of LC were identified. Post-SRS surgery was required in 35.8% due to progression. Treatment-related toxicity occurred in 21.4%, all Grade 1-2 and managed conservatively. CONCLUSIONS: SRS appears to be a safe option for patients with residual or recurrent SEGA who are unsuitable for further surgery. Despite modest LC rates, durable stabilization with minimal toxicity was achieved. Larger prospective studies are warranted to confirm these findings, optimize dosing and refine patient selection criteria. © 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.