Outcomes of Gamma Knife radiosurgery for meningiomas overlying the motor cortex

Meningiomas involving the motor cortex pose a therapeutic challenge due to the risk of treatment-related neurological morbidity. This study evaluates the clinical, imaging, and survival outcomes of patients with motor cortex meningiomas treated with Gamma Knife radiosurgery (GKRS).

Clinical, imaging, and survival data were retrospectively obtained from an institutional radiosurgery registry. Serial magnetic resonance imaging was reviewed to assess treatment volumes and longitudinal tumor response. Progression-free survival and tumor control were analyzed using standard survival methods.

Between 2008 and 2024, 47 patients with 58 meningiomas involving the motor cortex underwent either upfront definitive GKRS or adjuvant GKRS following surgical resection. Prescribed margin doses ranged from 12 to 17 Gy, normalized to the 50-80% isodose line. Patients with WHO Grade 1 meningiomas demonstrated significantly longer progression-free survival compared with those harboring Grade 2-3 tumors (p = 0.0014). Lesions with treatment volumes <5 cc were associated with superior progression-free survival relative to larger tumors (p = 0.0008). On univariate analysis, meningioma grade (p = 0.0014) and treatment volume (p = 0.0015) were significantly associated with tumor control. While GKRS Dmax showed only a marginal association with tumor control across the full cohort (p = 0.0882), a significant positive correlation between Dmax and percentage tumor volume reduction was observed in Grade 1 meningiomas (r = 0.53, p = 0.0287).

GKRS provides effective tumor control for meningiomas involving the motor cortex, particularly in patients with small-volume, WHO Grade 1 lesions. These findings support GKRS as a safe and efficacious treatment option in this eloquent location when careful patient selection and dose planning are applied.