Management of Refractory Seizures in Brain‑Tumor Patients

Assessment of Acute Seizure Worsening

• Obtain an urgent repeat MRI when breakthrough seizures occur, because in brain‑tumor patients they frequently signal tumor progression rather than medication failure. 1, 2, 3
• Perform an EEG to exclude non‑convulsive status epilepticus if the patient shows worsening neurological status or altered vigilance. 2, 3
• Screen for metabolic disturbances (e.g., hypoglycaemia, hyponatraemia), infectious complications, and treatment‑related neurotoxicity as possible contributors to seizure activity. 2, 3

First‑Line Maintenance Antiepileptic Therapy

• Transition from acute benzodiazepine use to maintenance therapy with levetiracetam (typically 1 g–3 g per day); it is the preferred first‑line agent in neuro‑oncology because of its efficacy, minimal drug‑interaction profile with steroids and chemotherapy, and good tolerability. 1, 2

Adjunctive Therapy for Refractory Seizures

• Approximately 30–40 % of patients remain uncontrolled on levetiracetam monotherapy; in these cases, the EANO‑ESMO guidelines recommend adding lacosamide as combination therapy. 1, 2
• Alternative add‑on agents include:
  
  • Valproic acid, which synergises with levetiracetam and has few cognitive side effects, but is contraindicated in women of child‑bearing potential. 2, 3
  • Lamotrigine, which may be used as an adjunct but requires several weeks to reach therapeutic levels. 1, 2

Medications to Avoid

• Enzyme‑inducing anticonvulsants (phenytoin, carbamazepine, phenobarbital) are contraindicated in brain‑tumor patients per EANO‑ESMO guidelines (Level III, Grade D) because they:
  
  • Interact significantly with dexamethasone used for cerebral edema. 1, 2
  • Interact with chemotherapy and targeted agents. 1, 2, 3
  • Have a worse side‑effect profile compared with non‑inducing agents. 2, 3

Role of Tumor‑Directed Therapy

• Surgical resection, radiotherapy, and chemotherapy each substantially reduce seizure frequency in patients with brain tumours. 2, 3
• Achieving tumour control is the strongest predictor of seizure control, especially in patients with brain metastases. 2, 3

Monitoring and Follow‑Up

• Measure serum anticonvulsant levels periodically to verify adherence, investigate treatment failure, and detect drug‑related toxicity. 1
• Ask patients about any seizure activity at every follow‑up visit. 1
• Continue anticonvulsant therapy until local tumour control is achieved through surgery, radiation, or chemotherapy. 2, 3

Common Pitfalls

• Do not maintain chronic benzodiazepine (e.g., diazepam) therapy for seizure control; benzodiazepines are reserved for acute emergencies.
• Do not attribute new or worsening seizures solely to medication failure without imaging, as they often indicate tumour progression. 1, 2, 3
• Monitor for psychiatric side effects (mood changes, behavioural disturbances) with levetiracetam; consider switching to lamotrigine if these occur. 1, 2

Management of Seizures in Patients with Cerebral Metastases

Initial Management

• The American Academy of Neurology recommends beginning anticonvulsant therapy immediately after the first seizure in patients with cerebral metastases, as secondary prophylaxis is indicated 4, 5
• Start levetiracetam as the first-line agent at doses of 1,000-3,000 mg/day, and continue treatment until local control is achieved through surgery, radiosurgery, or radiation therapy 5
• The National Comprehensive Cancer Network recommends against primary prophylaxis in patients without a seizure history, even in those with cerebral metastases 4, 5

Anticonvulsant Selection

• Levetiracetam is the preferred agent due to its lack of enzyme-inducing properties, avoiding drug interactions with steroids and chemotherapy agents commonly used in brain metastasis patients 5
• Levetiracetam does not require serum level monitoring and demonstrates efficacy with a significant percentage of patients achieving complete seizure control 5

Alternative Options

• Lamotrigine is a suitable alternative with good antiseizure activity, though it requires several weeks to reach therapeutic levels 5
• Lacosamide may serve as add-on treatment if monotherapy fails 5
• Valproic acid remains viable but should be avoided in women of childbearing potential due to teratogenicity 5

Drugs to Avoid

• The European Federation of Neurological Sciences recommends against the use of enzyme-inducing anticonvulsants (phenytoin, carbamazepine, phenobarbital) in brain metastasis patients due to significant drug interactions and worse side-effect profiles 4, 5

Duration of Therapy and Monitoring

• Continue anticonvulsants until local tumor control is achieved, and consider tapering within weeks after surgery if near gross total resection was achieved without recurrent tumor growth 5
• Question patients about seizure occurrences at each follow-up visit, and consider serum drug levels if seizures are not controlled or to assess compliance 5
• Obtain repeat MRI if seizures worsen, as this often indicates tumor progression 5