Seizures and Prostate Cancer: How Common, Causes, and Management

Short answer: Seizures are not a common symptom of prostate cancer itself, but they can occur in certain situations, such as when cancer spreads to the brain or from specific treatments that lower the brain’s seizure threshold. ^[1] Seizures linked to therapy are most notably reported with enzalutamide (Xtandi), while other causes include brain metastases, metabolic imbalances, stroke, or rare paraneoplastic autoimmune encephalitis. ^{[2] [1]}

How common are seizures in prostate cancer?

• Brain metastases are uncommon in prostate cancer compared with cancers like lung or melanoma, but when brain spread does occur, seizures can be one of the presenting symptoms. ^[1]
• Enzalutamide (Xtandi) can rarely cause seizures. In controlled trials excluding high‑risk patients, seizures occurred in about 0.5% of treated men; in a dedicated study of higher‑risk individuals, approximately 2.2% experienced seizures. [PM13] ^[2]
• When seizures occur after starting enzalutamide, they can arise anytime from weeks to several years into treatment, and therapy is typically stopped; events generally resolved in reported trials. ^{[3] [2]}

Main causes of seizures in people with prostate cancer

• Brain metastases (cancer spread to the brain): Brain tumors can trigger seizures by irritating brain tissue; typical symptoms of brain metastases include headaches, confusion, speech changes, weakness, balance problems, and seizures. ^[1]
• Treatment‑related lowering of seizure threshold:
  • Enzalutamide has a recognized seizure risk, especially in people with predisposing factors (prior head injury, stroke/TIA, medications that lower seizure threshold, space‑occupying brain lesions, Alzheimer’s disease, meningioma, leptomeningeal disease, prior seizures). ^{[4] [5]}
  • In higher‑risk groups, continuing enzalutamide after a first seizure sometimes led to a second event in a subset of patients. ^[6]
• Metabolic/medical issues: Electrolyte disturbances, infections affecting the brain, or stroke can provoke seizures in cancer settings. ^[7]
• Rare paraneoplastic autoimmune encephalitis: Some autoimmune syndromes associated with cancers can cause limbic encephalitis with prominent memory changes and seizures; this has been rarely reported in prostate cancer. [PM17] [PM18]

Warning signs that need urgent attention

• First‑time seizure, new neurologic symptoms, or seizure after starting enzalutamide warrant urgent medical evaluation to rule out brain metastases, medication effects, or metabolic triggers. ^{[2] [1]}

Evaluation: what tests are typically done

• Neurologic exam and imaging: Brain MRI (preferred) or CT to look for metastases or other lesions. EEG (electroencephalogram) may be used to assess ongoing seizure activity or risk. ^{[8] [1]}
• Lab work: Check electrolytes, glucose, renal and liver function, and infections that can provoke seizures. ^[7]
• Medication review: Identify drugs that lower seizure threshold or interact with seizure medicines, especially if using enzalutamide. ^{[4] [9]}

Management strategies

If seizures are due to brain metastases

• Local tumor control: Options may include steroids (to reduce swelling), surgery, stereotactic radiosurgery, or whole‑brain radiotherapy, tailored to the number, size, and location of lesions. Reducing tumor burden often reduces seizure frequency. ^[1]
• Antiseizure medicines: Levetiracetam is often preferred because it has fewer interactions with cancer therapies; enzyme‑inducing antiseizure drugs (like phenytoin, carbamazepine) can interact with chemotherapy and targeted agents, so careful monitoring is needed. ^[9]
• Onco‑epilepsy care: Multidisciplinary management by neurology and oncology teams helps control tumor‑related seizures; some people may still have seizures despite tumor resection and require long‑term antiseizure therapy. ^{[10] [11]}

If seizures are treatment‑related (e.g., enzalutamide)

• Stop or modify the offending drug: Enzalutamide is commonly discontinued after a seizure; risks and benefits of rechallenge are considered case‑by‑case, given reports of recurrent seizures in some who continued. ^{[2] [6]}
• Consider alternative therapies: Agents with lower central nervous system penetration, such as darolutamide, have not shown increased seizure rates in clinical development and may be considered when seizure risk is a concern. [PM15]
• Address predisposing factors: Review and minimize concomitant medications that lower seizure threshold and optimize control of vascular or neurocognitive comorbidities. ^[4]

If seizures are due to metabolic or autoimmune causes

• Correct metabolic triggers: Normalize electrolytes, treat infections, and manage stroke complications as appropriate. ^[7]
• Autoimmune encephalitis: Workup for neuronal autoantibodies may be considered if symptoms suggest limbic encephalitis; treatment often involves immunotherapy (e.g., steroids, IVIG, plasmapheresis) guided by neurology. [PM17] [PM18]

Practical safety tips

• Until medically cleared, avoid driving or operating dangerous machinery after a seizure episode. Seek urgent care for prolonged seizures (>5 minutes), repeated seizures without recovery, or new neurologic deficits. ^[7]
• Keep a seizure log and share it with your care team; note timing relative to cancer treatments, missed doses of antiseizure medicines, and triggers. ^[8]

Key takeaways

• Seizures are uncommon in prostate cancer, but can occur with brain spread or certain treatments like enzalutamide. ^{[1] [2]}
• Prompt evaluation helps identify the cause and guide targeted treatment, which may include imaging, antiseizure medications, and adjustments to cancer therapy. ^{[1] [8]}
• Collaborative care between oncology and neurology improves outcomes for tumor‑related seizures and complex cases. ^{[10] [11]}

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