ARTICLE IN BRIEF
Investigators reported that, except for simple partial seizures (SPS), 63 percent of patients remained “seizure free” two years after surgery, and 52 percent of patients were similarly doing well at the five-year mark. Ten years after surgery, 47 percent of patients were seizure free (not counting those with SPS). The probability of being totally seizure free at 10 years was 37 percent.
The long-term prognosis for patients who undergo surgery for epilepsy is good, according to a new study that tracked patients for as along as 19 years.
The study of 615 adults found that 63 percent of patients remained “seizure free,” apart from simple partial seizures (SPS), two years after surgery, and 52 percent of patients were similarly doing well at the five-year mark.
Ten years after surgery, 47 percent of patients were seizure free (not counting those with SPS). The probability of being totally seizure free at 10 years was 37 percent. At any given time during the duration of the study, nearly three-quarters of patients were seizure free in the previous year. [See “More About the Study.”]
Because the investigators followed patients for a long time, they were able to document patterns of remission and relapse, finding that “even in people with a long period of continuing seizures, the possibility of remission remains,” according to the report in the Oct. 15 edition of The Lancet.
“For seizure outcome, surgery is successful for many individuals in whom antiepileptic drugs have not been effective, but improvements need to be made to presurgical assessment to further increase rates of success,” the study concluded.
An editorial accompanying the study noted that surgery for medically refractory focal epilepsy has seen a resurgence over the past two decades, in part because advances in neuroimaging and invasive EEG are allowing for better identification of the surgical target. The editorialists noted, however, that while the research indicated favorable results in the first few years after surgery, not as much is known about what happens to patients as time goes by.
“In view of the long-term results of surgery shown, clinical practice needs to change with early referral of appropriate patients,” wrote the editorialists Ahmed-Ramadan Sadek, MD, and William Peter Gray, MD, of the University of Southampton, United Kingdom.
WHO FARED BEST?
The researchers ended up with more than 5,200 person-years of follow-up data after tracking patients for a median time of eight years. Younger patients tended to do better than older patients, and outcomes differed depending on the type of surgery.
“Patients who had extratemporal resections were more likely to have seizure recurrence than those who had anterior temporal resections,” the researchers reported, “whereas for those having lesionectomies, no difference from anterior lobe resection was recorded.”
Looking at the changes in patients over time, the researchers noted some patterns. For one, the status of patients was not necessarily static. During any give year, about 3 to 15 percent of patients changed seizure status, for instance going from no seizures to seizures or in the opposite direction.
“Those with SPS in the first two years after temporal lobe surgery had a greater chance of subsequent seizures with impaired awareness than did those with no SPS,” the study reported. “Relapse was less likely the longer a person was seizure free.”
The investigators noted that in 18 of 93 patients (19 percent), late remission was associated with introduction of a previously untried antiepileptic drug — 104 of 365 (28 percent) of seizure-free patients had discontinued drugs at the latest follow-up.
The researchers said they hoped that the outcomes would encourage doctors to refer candidates sooner for possible surgery.
“The average duration of epilepsy before coming for surgery is still 20 years,” John S. Duncan, DM, FRCP, FMedSci, professor of neurology at University College London Institute of Neurology and one of the study's investigators, told Neurology Today. “I would have hoped to see this coming down. There is still a lot of reticence among physicians to refer patients for surgical evaluation.”
He said patients should be considered as possible candidates for surgery “if focal seizures continue despite trying two to three epilepsy medications at full dose.”
QUALITY OF LIFE CONCERNS
Jerome Engel Jr., MD, PhD, the Jonathan Sinay Distinguished Professor of Neurology, Neurobiology and Psychiatry at the University of California, Los Angeles, said that epilepsy surgery is certainly not for every patient with intractable epilepsy, but he said it's “the most underutilized of all interventions.” He agreed that there needs to be more timely referral of patients.
“The longer you wait, the greater the psychological and social consequences of intractable epilepsy become,” he told Neurology Today. He said it would have been helpful if the study also had looked at quality of life, not just seizure activity.
“It's not only important whether patients stop having seizures,” Dr. Engel said. “It's also important to look at what effect (the surgery) has on their quality of life.”
Jacqueline French, MD, professor of neurology at New York University and co-director of Epilepsy Research and Epilepsy Clinical Trials at the NYU _Comprehensive Epilepsy Center, said that although the study results are positive, the findings should not be interpreted as “surgery or bust.”
“This only reflects on people who were considered to be good candidates for surgery. The results might turn out to be much different if other people were included. Unfortunately there are many patients who are not candidates, and were not included in the study,” said Dr. French, who also serves on the Neurology Today editorial advisory board. She noted that the results might not necessarily be replicable at other medical centers since the surgeries were done “at a single center with two surgeons and one philosophy on who should get operated on and who should not.”
She also pointed out that the study was not a randomized, controlled trial in which half the patients got surgery and the others were continued on medical therapy only.
Still, she said the study should help physicians and patients set realistic expectations for surgery, both before it happens and afterward. For instance, she said, it's important to know, as detailed in the study, that patients who had SPS in the first year after surgery were unlikely to go on to have recurrent disabling seizures. Knowing that could help in the decision on whether to continue antiepileptic drugs after surgery.
Andres Kanner, MD, professor of neurological sciences and psychiatry at Rush Medical College of Rush University in Chicago, said this latest study makes a good case for why surgery should be strongly considered for certain patients, and probably sooner rather than later.
“I think if anybody had any doubts about the efficacy of epilepsy surgery as an important treatment modality, this study really reinforces its potential benefits,” he told Neurology Today.
Dr. Duncan said his team is continuing to do a statistical analysis of what factors best predict a variable outcome in surgery.
MORE ABOUT THE STUDY
* The study tracked 615 patients who underwent epilepsy surgery at the National Hospital for Neurology and Neurosurgery in London, from February 1990 to October 2008.
* The majority of patients, 497, had anterior temporal resections, 40 had temporal lesionectomies, 40 had extratemporal lesionectomies, 20 had extratemporal resections, 11 had hemispherectomies, and seven had palliative procedures.
* Nearly all the surgeries were done by either one of two neurosurgeons. Follow-up data on seizure status was obtained from medical records and annual interviews with patients or a close relative.
* Five years after surgery, seizure-free rates (excluding SPS) were 55 percent for anterior temporal resection, 56 percent for temporal lesionectomy, 40 percent for extratemporal lesionectomy, and 64 percent for hemispherectomy.
* There was a difference in outcome noted for pathological changes after anterior temporal resection. Those with focal cortical dysplasia and other changes, including other malformations and no detected abnormality, had significantly earlier relapses than those with hippocampal sclerosis. The five-year seizure-free rates (excluding SPS) for anterior temporal resection were 57 percent for those with hippocampal sclerosis, and 63 percent for those with dysembryoplastic neuroepithelial tumor. There were some surgical complications reported: 46 superior quadrant visual field defects (8 percent of temporal lobe procedures); 28 (5 percent) wound infections needing antibiotics; three (less than 1 percent) hemipareses; 15 (2 percent) cases of frontalis muscle weakness; six (1 percent) cases of dysphasia; 19 (3 percent) cerebrospinal fluid leaks needing resuturing; and one deep venous thrombosis needing anticoagulation.