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Brain metastases
A patient with symptomatic brain metastases first gets dexamethasone; a small number of metastases is treated with SRS, a large symptomatic metastasis with surgery followed by SRS to the cavity, and whole-brain radiation is kept for extensive disease — with hippocampal avoidance and memantine to protect memory.
Why it matters in the exam
Brain metastases are among the most frequent topics in the radiation part, asked in almost every exam. Stems show a patient with lung cancer, breast cancer or melanoma and several brain lesions, and ask what first treats the symptoms, when SRS and when surgery, and which method was shown to reduce cognitive harm from whole-brain radiation.
Further topics are distinguishing radiation necrosis from recurrence, systemic therapy with good brain penetration that can defer radiation for small asymptomatic metastases (osimertinib, alectinib, tucatinib, ipilimumab with nivolumab), and the approach to leptomeningeal metastases. A common distractor is seizure prophylaxis for every patient.
Key points
- First treatment of symptomatic brain metastases is dexamethasone, and seizures are treated with levetiracetam.
- 1 to 4 metastases are treated with SRS, and adding whole-brain radiation harms memory without improving survival.
- A large symptomatic metastasis is treated with surgery, which quickly relieves mass effect and provides tissue for diagnosis, followed by SRS to the surgical cavity.
- When whole-brain radiation is needed, hippocampal avoidance with memantine reduces cognitive decline.
- Targeted drugs and immunotherapy with brain penetration can defer radiation for small asymptomatic metastases.
Summary table
| Situation | Treatment | Exam detail |
|---|---|---|
| Symptoms from oedema | Dexamethasone, at the lowest sufficient dose and for the shortest possible time | Levetiracetam only if a seizure occurred |
| 1 to 4 metastases (sometimes more if small in volume) | SRS | Versus SRS with whole-brain radiation: less cognitive harm, more new metastases, same survival |
| Large, symptomatic metastasis or one with mass effect | Surgery followed by SRS to the surgical cavity | Even when the diagnosis is unknown — surgery provides tissue |
| Many metastases or diffuse disease | Whole-brain radiation with hippocampal avoidance and memantine | The combination was shown to reduce cognitive decline |
| Small asymptomatic metastases with a treatable mutation | Systemic therapy with brain penetration and close MRI follow-up | Osimertinib, alectinib or lorlatinib, tucatinib in HER2, ipilimumab with nivolumab in melanoma |
| Radiation necrosis after SRS | Steroids, and in resistant cases bevacizumab | Perfusion MRI helps distinguish it from recurrence |
| Poor performance status and uncontrolled systemic disease | Supportive care only | Whole-brain radiation did not improve quality of life or survival in this situation |
In the full version for subscribers
- A simple algorithm
- Memory aid
- Exam traps
- 5 review cards
- Enough for IMLE
The full version is open to subscribers of: Oncology, Neurology, Neurosurgery, Internal medicine.
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Sources
- NCCN Clinical Practice Guidelines in Oncology: Central Nervous System Cancers, 2026 — Brain metastases
- ASCO-SNO-ASTRO Guideline: Treatment for brain metastases, 2021 — Recommendations
- Gunderson and Tepper's Clinical Radiation Oncology, 5th ed. (2021) — Brain metastases
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.