Using an advanced scanning technique, the scientists have identified a brain tumour, previously thought to be rare, which may be responsible for about 5 per cent of all serious cases of epilepsy.
Dr Simon Shorvon, a consultant neurologist at the Institute of Neurology in London where the research has been carried out, said yesterday that all patients with severe epilepsy which cannot be controlled by drugs should ask for a scan using Magnetic Resonance Imaging (MRI) to see whether they have the tumour. Epilepsy is a neurological disorder with more than one cause, which results in recurrent fits linked to abnormal electrical activity in the brain.
Speaking at the launch of the world's first brain scanning unit dedicated solely to epilepsy treatment and research, Dr Shorvon said that some patients, possibly 'several thousand', may have been told that their fits were due to an inoperable, malignant tumour and that they had only a short time to live. 'This is an understandable mistake. On less precise scans, such as a CAT scan, this is how it (the tumour) would appear,' he said.
But research over the last two years using MRI to create a three- dimensional picture of the brain has shown that the tumour, known as a dysembryoplastic neuro-epithelial tumour (DNT), is benign and suitable for surgical removal.
The results of the research, funded by the National Society for Epilepsy (NSE), will be published in the journal Brain shortly.
Dr Shorvon, who is medical director of the NSE, said that the work would also provide valuable clues to the development of malignant tumours. DNT was a unique, developmental type of tumour, which was on the 'borderland between cancer and a congenital anomaly', he said. It can occur in children or adults and in a variety of sites in the brain.
Patients who have fits or seizures are not screened by MRI routinely because of a shortage of machines and the cost - up to pounds 450 per 20- minute scan. 'Last year there were more MRI scanners in Boston than in the whole of this country. This has improved but provision is still inadequate,' Dr Shorvon said.
The new unit, which will open before the end of the year at the headquarters of the National Society for Epilepsy, at Chalfont St Peter, Buckinghamshire, means that many more NHS patients will have the option of an MRI scan paid for by the charity. Doctors there should be able to locate the precise site in the brain which causes epilepsy and decide whether surgery would help.
About 350,000 people in Britain suffer from epilepsy, including 100,000 children. The estimated number of people who would benefit from brain surgery is about 20,000, but only 150 operations are carried out each year.
Dr Shorvon said that patients could be referred by their GPs direct to the unit, which has received a pounds 1.2m donation from the pharmaceutical company, Glaxo.Reuse content