Contrary to earlier suspicions, epilepsy is not associated with an increased risk of cancer, researchers report.

“Epilepsy and long-term use of anti-epileptic drugs have been suggested to be associated with an increased risk of cancer,” Dr. Cecilia Adelow of the Karolinska University Hospital, Stockholm, and colleagues write in the Journal of Neurology, Neurosurgery and Psychiatry.

They investigated this notion by comparing people with various types of cancer to other similar but healthy people.

Specifically, the researcher identified 52,861 cases of blood cancers (leukemia, lymphoma, myeloma) and pancreatic cancer in the Swedish Cancer Registry from 1987 to 1999. A total of 137,485 controls were randomly selected from the Swedish Population Registry. The team linked cases and controls to the Swedish Hospital Discharge Registry to identify those who had been diagnosed with epilepsy.

A diagnosis of epilepsy 2 years or more before a cancer diagnosis was not associated with an increased risk of any of the types of cancer studied. This lack of association was also seen when an epilepsy diagnosis preceded a cancer diagnosis by more than 10 years.

“Although we have studied the association between a prior diagnosis of epilepsy and the risk of cancer, our negative findings also suggest that there is no major increase in risk with long-term use of…antiepileptic drugs regarding the types of cancer studied,” Adelow’s team points out.

While no evidence was found that epilepsy increases the risk of cancer, the investigators recommend that additional studies be performed to confirm these results.

SOURCE: Journal of Neurology, Neurosurgery and Psychiatry, June 2006.