Abstracts

RATIONALE: Low-grade neoplasms are responsible for up to 20% of cases of medically refractory epilepsy in some series. Tumor resection is known to improve seizure activity and quality of life in the short term. In this study, the reader will learn the long-term outcome of surgery for tumor-related medically refractory epilepsy with respect to seizure control and quality of life.
METHODS: The clinical records of all patients presenting with medically refractory seizures and low-grade gliomas who underwent evaluation at the Mayo Clinic between 1984 and 1990 were reviewed. Medically refractory seizures were defined as disabling seizures that continued despite trials of at least 2 antiepileptic drugs (AEDs) at therapeutic levels. Patients who underwent a presurgical epilepsy evaluation and tumor resection for the primary purpose of seizure control were included. Of 184 patients with tumor-related epilepsy, 42 met these criteria. Follow-up information was collected by questionnaire, which assessed several factors related to quality of life, tumor management, and seizure outcome. Categorical variables related to pre- and postoperative quality of life were analyzed with Chi-squared analysis, and Student[ssquote]s t-test was used to compare mean values related to pre- and post-operative seizure frequency and AED use. An [dsquote]excellent[dsquote] outcome was defined as a postsurgical score of 4 or less on the modified Engel Classification Scale.
RESULTS: 31 of 42 patients returned a completed survey, 3 had died, 1 refused to participate, 3 did not return a survey or follow-up phone calls, and 4 were lost to follow-up. The mean follow-up was 14 years (range 12 to 17). The mean monthly seizure frequency preoperatively was 21, the postoperative mean was 1.2 (p[lt]0.001). The mean number of daily AEDs decreased from 1.71 to 0.68 following surgery (p[lt]0.001). 19/31 (61%) respondents were seizure-free and 25/31 (81%) had an excellent outcome. 8/31 (26%) underwent additional surgery for either tumor or seizure recurrence. 9/22 (41%) patients old enough to drive prior to surgery did so, compared to 21/22 (95%) at present (p[lt]0.0002). Significant numbers of patients reported improvements in cognitive ability, and in the ability to work and socialize following surgery (p[lt]0.01). Emotional wellbeing and general quality of life were also significantly improved (p[lt]0.0001). 27/29 (93%) respondents expressed general satisfaction with their decision to undergo epilepsy surgery, and 25/30 (83%) reported no or mild morbidity related to surgery.
CONCLUSIONS: In this select group of patients who underwent resective surgery for low-grade tumor-related refractory epilepsy, 81% of respondents experienced an excellent outcome with a minimum of 10 years follow-up. This reduction in seizure frequency correlated with a significant improvement in quality of life. This study may prove useful in counseling patients with low-grade brain tumors and partial epilepsy who are being considered for surgical treatment.
[Supported by: Department of Neurology Discretionary fund]