Stereotactic Radiosurgery for Deep-seated Intraventricular Meningiomas: Efficacy, Safety, and Long-term Outcomes

Introduction: Intraventricular meningiomas (IVMs) are rare, constituting 0.5-3% of all intracranial meningiomas. Due to their deep-seated location, surgical resection of IVMs is associated with significant neurological morbidity, often requiring transcortical approaches. Stereotactic radiosurgery (SRS) provides a minimally invasive alternative for IVM management. This multi-institutional retrospective cohort study demonstrates the long-term outcomes of SRS in managing IVMs.

Methods: We conducted a multi-institutional retrospective cohort analysis of patients with IVMs treated with SRS. Patients were identified from institutional databases and included if they underwent SRS for primary, residual, or recurrent IVM. Collected data included demographics, clinical presentation, imaging characteristics, treatment parameters (marginal dose, maximum dose, isodose line, and V12Gy), and follow-up outcomes. Local control and complications, including peritumoral edema and cyst formation, were evaluated.

Results: A total of 94 patients (60 females) from five institutions with a median age of 54.5 years (range 14–86) were included. The predominant presenting symptoms were headache and visual disturbances. The lateral ventricle was the most common tumor location (88.3%). The median tumor volume was 4.8 cc (range 0.16–17.0 cc), and the median marginal dose was 13 Gy with a median isodose line of 50%. Kaplan-Meier analysis estimated a PFS rate of 87.2% at 60 months. Log-rank tests indicated no significant differences in PFS based on tumor volume, V12 dose, or presence of edema (p > 0.05). Logistic regression suggested a trend toward increased risk of post-SRS edema with larger tumor volumes. Radiation-induced changes were observed in 24 patients, while symptomatic edema developed in 13 patients, with a mean onset of 9.3 months post-SRS. Symptomatic cases were successfully managed with short-term steroids; Symptomatic cases were successfully managed with short-term steroids; only one patient required bevacizumab, and another required surgical resection.

Conclusion : GKRS is an effective and safe treatment for IVMs, offering favorable local control and symptom relief with minimal invasiveness. Our findings suggest that SRS provides a viable alternative to resection, especially for deep-seated IVMs, with low rates of adverse effects.