Abstracts

Rationale: It is well known that the patients with low-grade glioma develop epilepsy at a high rate. Treatment and observation period of low-grade glioma often last for years. Control of epileptic seizure is one of important issues in the treatment of low-grade glioma during the therapy. We examined appearance pattern of the epilepsy with low-grade glioma. Methods: We listed supratentorial low-grade glioma (WHO grade 1 and 2) which was newly diagnosed from 2000 to 2015. We extracted 70 patients whom we followed up more than one year after surgery. The data were provided from the confirmation of the medical record or the confirmation with the telephone. Results: Seventy patients involved 7 pilocytic astrocytoma (PA), 21 diffuse astrocytoma (DA), 34 oligodendroglioma (OG), and 8 oligoastrocytoma (OG). Surgery performed at 16-79 y/o (median 48.5). Following up periods was 1-15 years (median 4.7). Fifty-seven % (40/70) of the patients developed seizure (PA 43% (3/7), DA 52% (11/21), OG 59% (20/34), OA 66%(6/8). Eighty-three % (33/40) of the seizure was generalized seizures. Antiepileptic drug was started in all patients who had presurgical seizure. One patient without presurgical seizure started antiepileptic drug. After perioperative periods, seizure occurred in 31% of the patients (22/70: PA 29% (2/7), DA 38% (8/21), OG 24% (9/34)?OA 38%(3/8)). Serious seizure did not occur in perioperative periods. One patient became drug resistant. The patients with presurgical seizure experienced postsurgical seizures in 48% (19/40). The postsurgical seizure occurred within 2-years after surgery in 74% (14/19). After more than two years of seizure free period, remaining five people (5/19; 26%) had a relapse of epileptic seizures, and all 5 patients attributed to tumor recurrence or malignant transformation. Three of 30 patients without presurgical seizure (10%) had first seizure after surgery, and all three did not provide suggestive evidence of tumor regrowth. There were no correlation between the extent of tumor resection and seizure prognosis. Conclusions: The patients with low grade glioma who experienced preoperative seizures, are at high risk of seizure recurrence, even if antiepileptic drugs have been administered. It is necessary to think about the recurrence or malignant transformation of the tumor, when an epilepsy attack occurs after a long seizure remission. Funding: no