Seizures common in survivors of pediatric brain tumors

NEW YORK - Many children who survive brain tumors have seizures, according to a new study.

Overall, 24% of pediatric brain tumor survivors in the study had seizures and 14% of them had refractory seizures or were still on medications at the most recent follow-up, the authors report.

Tumor pathology, cortical location and subtotal resection predisposed patients to seizures, and residual tumor presence and longer duration from diagnosis predicted poor seizure control, they report in Epilepsia, online August 31.

"These findings may impact how we follow long-term survivors of childhood brain tumors and the level of vigilance that providers must have to the possibility of neurologic late effects long after completion of treatment," said lead author Dr. Nicole J. Ullrich from Dana-Farber/Boston Children's Cancer and Blood Disorders Center in Boston.

"This information will allow clinicians to better understand which patients need to remain on anti-seizure medications and which may be able to come off sooner," she told Reuters Health by email.

"As some patients require chemotherapy after diagnosis and some anti-seizure medications can interact with chemotherapy, this will be crucial to clinical management. These patients may be more susceptible to the side effects of anti-seizure medications, so helping to determine who can come off sooner will likely improve overall function," Dr. Ullrich added.

The mean follow-up duration was 7.6 years. In 109 patients, the initial surgical resection was gross-total and in 143, it was subtotal. Biopsy alone was performed in 29 patients, while 17 had no surgical intervention.

Tumors occurred in the posterior fossa in 36% of the children, in the midline in 34%, in the cortex in 29% and elsewhere in 3%. The most frequent diagnoses included low-grade glioma, medulloblastoma, and ependymoma; 163 patients had cranial irradiation and 127 had chemotherapy.

Tumors recurred in 30%, and seizures occurred in 71 patients (24%), with 42 (14%) having ongoing seizures at the most recent follow-up.

"As treatments for childhood brain tumors continue to result in improved overall survival, clinicians have observed the emergence of significant neurologic toxicity and neurologic late effects, including seizures, often many years after treatment completion," Dr. Ullrich said.

"The question of whether patients with a primary brain tumor require prophylactic/preventative treatment with anti-seizure medications remains unanswered. In addition, the question of how long to maintain a patient on anti-seizure medications, especially in the setting of residual tumor, is challenging and dependent on multiple clinical factors," she added.

Dr. Kevin F. Ginn, director of the Pediatric Brain Tumor Program at Children's Mercy Hospital Cancer Center in Kansas City, Missouri, said in an email, "Although this study adds to the identified risks of seizure in survivors of pediatric brain tumors, it remains a challenge to determine which patients need anti-epileptic medications and when it is truly appropriate to stop them."

"The authors pointed out that, due to the nature of their study, patients who stopped anti-epileptic medications during the study could not be followed for seizure recurrence," Dr. Ginn, who was not involved in the study, told Reuters Health. "This is an important point, as we need better predictors of which patients can safely stop medications."

Asked how the study might affect patient care, Dr. Raja B. Khan, chief of the neurology division of St. Jude Children's Research Hospital in Memphis, Tennessee, said it "probably will not make a difference to those who are familiar with the literature and take care of these patients on a regular basis."

"However, it may help bring understanding of the issue to primary care physicians who may have only a few such patients in their practice," Dr. Khan, who was also not involved in the study, told Reuters Health by email.

SOURCE: http://bit.ly/1V7Gknz

Epilepsia 2015.

References: Reuters Health
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