Do we have to continue antiseizure medications post surgery in long-term epilepsy associated tumors (LEATs)?

OBJECTIVE: To identify the rate of successful antiseizure medication (ASM) withdrawal after resective surgery in patients with long-term epilepsy-associated tumors (LEATs). METHODS: A retrospective analysis (from our prospectively archived data) on the post-operative ASM profile of 123 consecutive patients who completed a minimum of 2 years after resection of LEATs for ASM-resistant epilepsy. A comparison between recurred and non-recurred groups in terms of seizure recurrence was used to identify the potential predictors of seizure recurrence whose attributes were further analyzed using univariate and multiple logistic regression analysis. Kaplan-Meier survival curves were used to study the probability of ASM freedom following surgery. RESULTS: We attempted ASM withdrawal in 102 (82.9 %) patients. Forty-eight (47.1 %) had seizure recurrence while reducing ASM, of which 22 (21.6 %) continued to have seizures even after ASM optimisation. On univariate analysis, presence of pre-operative secondary generalized seizure(s) was the only factor associated with seizure recurrence. At a mean follow-up of 6.1 years, 72 (58.5 %) patients were seizure-free and aura-free at terminal follow-up (53 patients were off any ASM). The cumulative probability of achieving complete ASM-free status was 29 % at fourth year, 42 % at sixth year, 55 % at eighth year, and 59 % at 10th year after surgery. CONCLUSIONS: Following resective surgery for LEATs, ASM(s) could be successfully discontinued in half of the patients. About one-third of the patients may have recurrent seizures on follow-up. Presence of secondary generalized seizure(s) prior to surgery predicts seizure recurrence, whereas MRI defined completeness of resection will not. This information will help in rationalising decisions on ASM management post-resection.