Long-term surgical outcomes of temporal lobe epilepsy associated with low-grade brain tumors

Tumor-related temporal lobe epilepsy (TLE) has a high likelihood of medical intractability and requires surgical treatment. The aims of this study were to analyze the long-term surgical outcomes of and to present appropriate surgical strategies for tumor-related TLE.

The clinical data of 87 consecutive patients diagnosed with tumor-related TLE were analyzed. The median age at surgery was 22 years. Sixteen patients had a tumor confined to the amygdala or the parahippocampal gyrus, and 10 of them received a tailored lesionectomy without hippocampectomy. The surgical outcome was evaluated based on 3 aspects: seizure control, tumor control, and discontinuation of antiepileptic drugs (AEDs).

The actuarial seizure and tumor control rates at the fifth year postoperatively were 79% and 90%, respectively. Seizure control was highly correlated with tumor control. The following factors were found to be significantly associated with poor seizure control: duration of epilepsy>10 years, presence of a remote focus on surface electroencephalography, and incomplete tumor removal. The actuarial AED maintenance rates were 47% at the second year and 11% at the fifth year. The median time to AED discontinuation was 22 months. A younger age at surgery was found to be significantly associated with an increased chance of AED discontinuation. Tailored resection focusing on the tumor resulted in a favorable outcome, even for tumors confined to the amygdala or the parahippocampal gyrus.

Surgical treatment of tumor-related TLE resulted in long-term seizure control in the majority of patients. Maximal tumor removal can be recommended for tumor-related TLE.