Patient Considerations and Current Clinical Evidence (continued)

Patients with high-grade gliomas (the most common type of primary brain tumor) who experience seizures are commonly treated with valproic acid, phenytoin, carbamazepine, or levetiracetam, for example; while the neurocognitive effects of these drugs are not well known, cognitive deteriorations have been reported among patients treated with these drugs.11  Valproic acid sometimes triggers acute encephalopathy (which can mimic tumor progression effects) and thrombocytopenia.7 However, a recent cohorts-comparison study of 117 patients with high-grade glioma found that while phenytoin is associated with cognitive declines, valproic acid and levetiracetam do not appear to be associated with cognitive declines in attention, executive functioning, verbal memory, working memory, psychomotor functioning, or information processing speed.11 Indeed, for verbal memory, at least, both levetiracetam and valproic acid might even improve patient cognitive functioning, the authors reported.11


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Oxcarbazepine, like levetiracetam and valproic acid (in the absence of acute encephalopathy), appears not to significantly impair neurocognition, and might improve attention function.7  However, because the potentially beneficial associations of oxcarbazepine, valproic acid (in the absence of acute encephalopathy), and levetiracetam are based on retrospective studies of small numbers of patients, it is not clear that potential cognitive benefits should be part of clinical decision-making about the administration of these antiepileptics.

Conclusion

While epileptic seizures remain a frequently encountered effect of certain types of brain cancers, much research is still needed to determine when and which pharmacologic treatment option—where appropriate—should be used. Recent data suggest there may be a role for the different antiepileptics; however, more information is still necessary to confirm not only which patients are likely to benefit but also which agent is optimal, based on the tumor type. More clinical trials can help provide more insight in this area.


References

1. Weller M, Stupp R, Wick W. Epilepsy meets cancer: when, why, and what to do about it? Lancet Oncol. 2012;13(9):e375-382.

2. Hamasaki T, Yamada K, Yano S, et al. Higher incidence of epilepsy in meningiomas located on the premotor cortex: a voxel-wise statistical analysis. Acta Neurochir (Wein). 2012;154(12):2241-2249.

3. Kahlenberg CA, Fadul CE, Roberts DW, et al. Seizure prognosis of patients with low-grade tumors. Seizure. 2012;21(7):540-545.

4. Wu L, Wu J, Zhang H. Hypoglycemia-induced convulsive status epilepticus as the initial presentation of primary hepatic carcinoma. Neurol Sci. 2012;33(6):1469-1471.

5. Allen NM, Moran MM, King MD. Not all twitching is epileptic! Hand myoclonus in a boy with spinal cord tumor. J Pediatr. 2013; 162(2):431-431.e.1.