# Persons with epilepsy have an elevated radiosensitivity, which may be mitigated by folic acid

## TL;DR

People with epilepsy are more sensitive to radiation, but this sensitivity may be reduced by folic acid, especially in women.

## Contribution

This study identifies increased radiosensitivity in epilepsy patients and suggests folic acid as a potential mitigating factor.

## Key findings

- Persons with epilepsy showed higher radiation sensitivity than healthy individuals and cancer patients.
- Male epilepsy patients were more radiosensitive than females, possibly due to lower folic acid intake.
- Perampanel and lacosamide, antiseizure medications, increased radiation sensitivity.

## Abstract

Patients undergoing radiotherapy for cancer usually have several other comorbidities and are taking various medications. Both of these factors can affect the individual radiation sensitivity of normal tissue. We therefore studied persons with epilepsy (PWE) to determine whether they had altered radiation sensitivity.

Blood samples were collected from 105 adult patients with epilepsy and compared to those of healthy individuals and oncological patients. The samples were irradiated ex vivo and analyzed by 3-color fluorescence in situ hybridization. In each patient, aberrations were analyzed in 200 metaphases of chromosomes 1, 2, and 4 and scored as breaks. Radiosensitivity was determined by mean breaks per metaphase (B/M) and compared to both healthy donors and oncologic patients.

Radiosensitivity (B/M) of the PWE (n = 105, B/M: 0.478) was clearly increased compared to healthy individuals (n = 209, B/M: 0.420) and oncological patients (rectal patients and breast cancer patients, n = 319, B/M = 0.442). Antiseizure medications tended to increase radiation sensitivity. The use of perampanel (0.505 B/M; p = 0.081) and lacosamide (0.521 B/M; p = 0.014) led to a clear increase in radiation sensitivity. Male PWE (0.502B/M, p = 0.004) were distinctly radiosensitive which may be potentially explained by the fact that women were recommended to take high doses of folic acid according to German guidelines at the time of the study. Factors like seizure frequency, epilepsy duration, polytherapy and comedication did not contribute to increased radiosensitivity.

PWE were clearly increased radiosensitive compared to healthy individuals and oncological patients. Male PWEs were found to be more sensitive than female PWEs. This may be due to their higher intake of folic acid, a substance which can protect against radiation.

The online version contains supplementary material available at 10.1007/s00415-025-13593-0.