According to a report in this week’s surgery special issue of The Lancet, approximately half of all patients who had undergone surgery for epilepsy remain seizure free after 10 years. Although, there is room for more improvement regarding pre-surgical evaluation and surgical treatment for individuals with chronic epilepsy. The article is written by Jane de Tisi, Dr Gail S Bel, and Professor John Duncan, National Hospital for Neurosurgery, and Imperial College London, and team.
In the study, researchers determined the long-term outcome for adults who had undergone epilepsy surgery by establishing relapse and seizure remission patterns after surgery. The long-term outcome of surgery for epilepsy in 615 adults was examined (497 patients received anterior temporal resections, 40 extratemporal lesionectomies, 40 temporal lesionectomies, 20 extratemporal resections, 11 hemispherectomies, and 7 palliative procedures [corpus callosotomy, subpial transection]), with a median yearly follow-up of eight years.
Apart from simple partial seizures (SPS), they estimated that at 5 years after surgery 52% of patients remained seizure free, and at 10 years 47% of patients remained seizure free. Compared to patients who had anterior temporal resections, those who had extratemporal resections were two times as likely to have seizure recurrence. No difference was recorded for patients who received temporal lesionectomies from those who received anterior temporal lobe resection. Patients with simple partial seizures in the initial two years following temporal love surgery were two and half times more likely to suffer from subsequent seizures with decreased awareness compared to patients with no SPS. The longer a patient was seizure free the less likely they were to relapse, conversely, the longer seizures continued the less likely the patient went into remission. In 19% (18 out of 93 individuals), late remission was connected when they began a previously untried antiepileptic drug. 28% of individuals (104 of 365) seizure-free had stopped taking drugs at the latest follow-up.
They revealed that after epilepsy surgery, 40% of patients are completely seizure-free in the long-term, and a further 11% of patients only having SPS. However, even though 82% of patients were free from seizures or SPS for at least 1 year, this does not indicate cure. Not one patients epilepsy became significantly worse. The researchers explain that clinical practice should change in order to refer suitable patients for potential surgery sooner. Currently, surgery is only considered for focal epilepsy and only if drugs have not been effective in controlling the patient’s seizures for more than two to three years. In order to more accurately identify patients who will benefit from surgery and to increase success rates, selection process and surgical methods need to be improved. They say that some previous investigations could have implied over-optimistic expectations.
The new discovery that simple partial seizures continuing in the initial first two years following surgery increases the probability of seizures recurring in patients in comparison to those completely seizure free has never been reported previously. This crucial finding may affect the decision to decrease or continue antiepileptic medications. However, the researchers found it interesting that the majority of the patients who were seizure free following surgery decided to continue taking an antiepileptic drug. No anticipated randomized trial is available of stopping or continuing these drugs following surgery, and patients’ decisions making may be based on major factors, such as pregnancy or learning how to drive.
They explain that taking these drugs is not a bar to driving. The important thing is that patients remain seizure free for 12 months and continue to be free of seizures. If a single antieplieptic drug is taken during pregnancy there is a 2-3% risk of a major congenital malformation, if the women is seizure free after surgery and is thinking about getting pregnant, she might consider stopping the medication before conception.
The researchers conclude:
“For seizure outcome, surgery is successful for many individuals in whom antiepileptic drugs have not been effective, but further improvements need to be made to presurgical assessment to further increase rates of success.”
In a joint comment, Dr Ahmed-Ramadan Sadek, and Professor William Peter Gray, Wessex Neurological Centre, Southampton University Hospitals NHS Trust and University of Southampton, UK, explain that the new data will be helpful for counselling epilepsy patients and guiding their physicians. They conclude:
“This study validates the long-term effectiveness of epilepsy surgery showing that over 50% of all patients are rendered continuously long-term seizure free; it also raises important questions and challenges. Are the benefits of seizure freedom apportioned equally to the continuous and later remission groups? Can selection and reselection strategies be further improved to optimise long-term seizure control? Finally, the median duration of epilepsy before surgery in this study was 20 years. In view of the long-term results of surgery shown, clinical practice needs to change with the early referral of appropriate patients.”
Written by Grace Rattue