Abstracts

Rationale: The risk of seizures in patients with meningiomas is well recognized, but few studies focus on seizure outcomes after surgical resection. Determining which patients benefit from continued anti-epileptic drug (AED) therapy after surgery can be difficult. We sought to identify characteristics predictive of post-operative seizures in newly diagnosed patients who underwent surgical resection of a meningioma. Methods: Demographic and clinical variables were evaluated retrospectively as predictors of post-operative seizures, defined as occurring more than 14 days after surgery, in 149 patients with newly diagnosed meningiomas treated between 2006 and 2011. Results: Median follow-up was 41 months (2-388). Forty-one (28%) patients experienced a pre-operative seizure and 50 (35%) a post-operative seizure. Of those 50, 28 (56%) were not on AEDs at the time of their seizure. In 29 (58%) patients, this was in the absence of recurrence. RT was part of the initial treatment in 18 (12%) patients; 5 (28%) developed seizures following RT. Male gender, higher grade (Grade II: hazard ratio [HR] 2.57, 95% confidence interval [CI] 1.44-4.57, P=0.001; Grade III: HR 3.64, CI 1.31-10.12, P=0.013), parietal location (HR 2.62, 95% CI 1.26-5.43, P=0.01), pre-operative seizures (HR 5.41, 95% CI 3.08-9.50, P<0.001), and post-operative RT (HR 6.17, 95% CI 3.33-11.46, P<0.001) were significantly associated with an increased risk of post-operative seizures. Pre-operative seizures (HR 6.96, 95% CI 3.49-12.45, P<0.001) and RT (HR 8.10, 95% CI 4.29-15.31, P<0.001) were identified as independent predictors in the multivariable model, but tumor grade was not (p<0.24).Conclusions: Pre-operative seizures predict an increased risk of post-operative seizures in patients undergoing surgical resection of meningiomas. These patients are most likely to benefit from continued treatment with anti-epileptic medications post-operatively. However, further investigations are needed to clarify the role of RT.