Early Surgery Deemed Best for Drug-Resistant Epilepsy

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Early Termination Warrants Caution

Even though the benefit of surgery in the ERSET study appeared to be substantial, "results of trials that are terminated very early should be interpreted with caution, especially when termination is not based on prespecified rules, because of the risk of bias," wrote Dr. Donald L. Schomer and Dr. Roger J. Lewis. This is because "during any clinical trial, random fluctuations in observed treatment effects are seen over time, although the relative magnitude of these variations decreases as cumulative data increase."

The sample size in the study ultimately was "quite modest and limits the precision in the estimate of the treatment effect; however, the observed treatment effect was so large that the benefit of [surgery] seems unequivocal," they concluded.

Dr. Schomer is in the department of neurology at Beth Israel Deaconess Medical Center and Harvard University, Boston. Dr. Lewis is in the department of emergency medicine at Harbor-UCLA Medical Center. Dr. Schomer reported being the founder of SleepMed/Digitrace Inc., a medical service company, and Dr. Lewis reported ties to Berry Consultants, a statistical consulting firm that designs clinical trials. These remarks were taken from their editorial accompanying Dr. Engel’s report (JAMA 2012;307:966-8).



Nevertheless, the sample size in this study "was too small to permit a definitive conclusion that early surgery does not present a greater risk for cognitive disturbances than continued pharmacotherapy," they added.

Overall, the ERSET results "reinforce the view that surgery soon after failure of two antiepileptic drug trials offers the best chance of preventing a lifetime of disability," Dr. Engel and his colleagues said.

The findings also remind clinicians that "all patients with epilepsy should be referred to an epilepsy center as soon as trials of 2 antiepileptic drugs fail, and surgery should be performed," they added.

The ERSET study was supported by the National Institute of Neurological Disorders and Stroke and the National Institutes of Health. Several of the authors reported receiving consultancy fees, lecture or speakers bureau fees, or travel expense fees from manufacturers of devices and drugs to treat epilepsy.


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