Abstracts

Rationale: For a subset of patients with refractory focal epilepsy, epilepsy surgery to remove the epileptogenic zone offers a substantial chance for seizure freedom. Laser interstitial thermal therapy (LITT) is a minimally invasive approach for tissue ablation using thermotherapy under MRI-guidance. For mesial temporal lobe epilepsy, LITT offers outcomes that are comparable to open resection with lower short-term morbidity and potentially lower risk for long-term morbidity. We sought to understand how patients assess treatment alternatives for refractory temporal lobe epilepsy. Specifically, we sought to determine patient acceptability of benefit-risk tradeoffs in selecting treatment options, including open brain surgery, laser ablation (laser interstitial thermal therapy, LITT) and continued medications.

Methods: A discrete-choice-experiment survey was developed in consultation with patient advisors and refined using single-patient interviews. The survey consisted of 20 versions, each of which was randomly assigned to respondents. Each version had 8 sets of constructed treatment alternatives, representing open brain surgery, LITT, or continued medical management. For each set, respondents indicated the treatment alternative they would choose first. Treatment alternatives were characterized according to varying hypothetical levels of the chance of seizure freedom for at least two years (20% to 70%), risk of 30-day mortality (0% to 10%), and risk of neurological deficits (0% to 40%). Medical management offered no chance of seizure freedom, but no additional risks. Respondents’ treatment choices were analyzed using random-parameters logit models, and the results were used to quantify acceptable benefit-risk tradeoffs. Preference heterogeneity was evaluated using latent-class analysis.

Results: The online survey was administered to two cohorts of adult patients with refractory epilepsy: a Duke cohort identified using diagnostic codes (n=106) and a commercial panel of patients with a self-reported physician diagnosis of refractory epilepsy (n=300). Based on mean preference weights pooled across both cohorts, respondents who indicated a willingness to consider a surgical intervention would accept a reduction in the chance of seizure freedom from 70% to a minimum-acceptable benefit of 23% if they could undergo LITT rather than open brain surgery. For a reduction in 30-day mortality from 1% to 0%, the minimum-acceptable benefit was 52%. For a reduction in risk of long-term deficits from 10% to 0%, the minimum chance of seizure freedom considered acceptable was 39%. Latent-class analysis revealed additional choice patterns identifying respondent groups that more strongly favored continuing medication therapy or undergoing surgical interventions.

Conclusions: Patients who are receptive to surgical interventions would, on average, accept significantly lower treatment effectiveness to undergo a minimally invasive procedure relative to open brain surgery. They also were willing to accept lower treatment benefit to reduce risk of mortality and neurological deficits.

Funding: Please list any funding that was received in support of this abstract.: The study was supported through a research agreement between Duke University and Monteris Medical Corporation.