Seizures can develop as a late effect long after cancer treatment finishes, often resulting from brain tissue scarring, the lingering impact of cranial radiation, or secondary changes in the brain. While acute seizures usually happen during active drug therapy, late-onset or refractory epilepsy can emerge years later, requiring careful medical evaluation and long-term management.

Potential Causes of Late-Onset Seizures

• Radiation therapy changes: Brain scarring or localized tissue damage from past radiation can alter electrical pathways over time
• Prior surgery or structural shifts: Past tumour removal or tissue changes can create an epileptogenic focus that triggers seizures months or years later
• Recurrence or new lesions: A return of the primary tumor or new intracranial spread must always be ruled out
• Vascular or metabolic factors: Late cerebrovascular complications or chronic systemic shifts can provoke abnormal brain activity

Evaluation and Management

• Diagnostic testing: Doctors typically use an electroencephalogram (EEG) to check for brain wave abnormalities and neuroimaging (like an MRI or CT scan) to view structural changes
• Medication choices: Treatment often involves anti-seizure medications, with non-enzyme-inducing agents preferred to avoid interfering with other health conditions or remaining treatments
• Safety planning: Guidance on driving restrictions, home safety, and recognizing early warning signs forms a critical part of ongoing care

Please see your GP if you are having seizures