Postoperative seizure control in patients with tumor‐associated epilepsy

Summary Objective The patterns of postoperative seizure control and response to antiepileptic drugs ( AED s) in tumor‐associated epilepsy ( TAE ) are poorly understood. We aim to document these characteristics in patients with supratentorial gliomas. Methods This was a retrospective analysis of 186 patients with supratentorial gliomas. Seizure patterns were classified into four groups: A, no postoperative seizure; B, early postoperative seizure control within 6 months; C, fluctuating seizure control; and D, never seizure‐free. Rates and duration of seizure freedom, subsequent seizure relapse, and response to AED were analyzed. Results Among patients included, 49 (26.3%) had grade II , 28 (15.1%) had grade III , and 109 (58.6%) had grade IV glioma. Outcome pattern A was observed in 95 (51.1%), B in 22 (11.8%), C in 45 (24.2%), and D in 24 (12.9%). One hundred nineteen patients had at least one seizure and were classified as having TAE . Compared to pattern A, pattern B was predicted by histologic progression; pattern C by tumor grade, preoperative seizure, and histologic progression, and pattern D by preoperative seizure and gross total resection. Among patients with TAE , 57.5% of grade II , 68.2% of grade III , and 26.3% of grade IV experienced a period of 12‐month seizure freedom. After first 12‐month seizure remission, 39.1%, 60.0%, and 13.3% of grade II , III , and IV gliomas, respectively, experienced subsequent seizure; 22.6% of those with TAE reached terminal seizure freedom of at least 12 months on their first postoperative AED regimen, 6.5% on their second regimen, and 5.4% on subsequent regimens. Significance Distinct patterns of postoperative seizure control exist in gliomas; they have specific risk factor profiles, and we hypothesize these correspond to unique pathogenic mechanisms. Twelve‐month seizure freedom with subsequent relapse is frequent in grade II – III gliomas. Response to AED s is markedly poorer than with non‐ TAE , highlighting the complex epileptogenicity of gliomas.