Prevent seizures. If you have previously had a seizure because of your tumor, you will need to take seizure meds for a while. If you have not previously seized, then the meds are simply used as a precaution to prevent future seizures. The use of prophylactic seizure meds is currently being studies and mildly controversial. I personally do use seizure meds in all my malignant brain tumor patients.
Risk of seizure . Any trauma or abnormality including tumor recurrence can dramatically increase risk for having a seizure. The manipulation alone during the surgery can result in abnormal electrical activity. Anti seizure medication is used to protect the brain as a precaution.