Seizures After Stereotactic Radiosurgery for Benign Supratentorial Meningiomas: An Uncontrollable Type of Seizure?

Objective: We investigated seizure outcomes of patients with supratentorial meningiomas (ST-MNGs) treated with stereotactic radiosurgery (SRS).
Methods: One hundred and thirty-three patients with a total of 144 ST-MNGs, who were treated with SRS between 2009 and 2016, were included in this study. The mean age was 59.0 ± 11.9 years (range, 13-87 years). The mean follow-up duration was 49.8 ± 24.5 months (range, 9-96 months). The median tumor volume was 2.60 cm ³ (range, 0.06-32.40 cm ³ ), and the median marginal dose was 14.0 Gy (range, 11.0-20.0 Gy). Postradiosurgery peritumoral edema (PRPTE) was developed in 43 lesions (29.9%).
Results: New seizure attacks developed in 16 patients (12.0%) after SRS (first seizure attack in 14 [87.5%]; seizure aggravation in 2 [12.5%]). In 15 patients with new seizure attacks (93.8%), PRPTE was proved on magnetic resonance imaging. The mean interval between SRS and new seizure attack was 6.6 ± 7.1 (range, 0.23-28.8) months. Simple partial seizure was the most common type of seizure (n = 9 [56.3%]). Five patients (31.3%) were seizure-free with antiepileptic drug (AED) medication (3 [18.8%] withdrew AEDs during the follow-up period); however, the remaining 11 patients (68.7%) did not achieve seizure-free outcomes even with AED medication. Moreover, seizures became intractable in 8 patients (50.0%). From multivariate analysis, the significant predictors of post-SRS seizure attack were PRPTE (odds ratio, 53.99; 95% confidence interval, 5.214-559.1; P = 0.001) and brain-tumor contact-surface index (odds ratio, 2.466; 95% confidence interval, 1.183-5.138; P = 0.016).
Conclusions: The clinical outcomes of seizures after SRS for ST-MNGs fall short of our expectation, and seizures seem to be uncontrollable and even intractable.
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