Brain Metastases
Related Subjects:
|Hypercalcaemia
|Neutropenic Sepsis
|Pulmonary Embolism
|Superior vena caval obstruction syndrome
|Cerebral Metastases
|Metastatic bone disease
|Oncological emergencies
🌐 Brain Metastases are the most common intracranial tumours in adults. Whole-brain radiotherapy remains a key treatment, though management is increasingly tailored with surgery and stereotactic radiosurgery.
📌 About
- 🫁 Lung cancer is the most frequent cause of brain metastases.
- Other common primaries: breast, kidney, melanoma, testicular tumours, and colorectal cancers.
- 80% occur in the cerebral hemispheres; ~20% are posterior fossa.
- Typically lodge at the grey–white junction or watershed zones (MCA–PCA borders).
🧬 Aetiology
- Hematogenous spread, with tumour emboli seeding cortical and subcortical vessels.
- Predilection for vascular junctions due to abrupt calibre change in vessels.
- Histologies prone to haemorrhage: melanoma, choriocarcinoma, lung, thyroid, renal carcinoma.
📊 Common Primary Sources
- 🫁 Lung cancer
- 👩🍼 Breast cancer (esp. ductal type → cerebellar deposits)
- 🧪 Testicular germ cell tumours
- 🩸 Renal cell carcinoma
- 🖤 Malignant melanoma
- Less common: colorectal, ovarian, prostate, thyroid
📍 Location Tendencies
- Breast/prostate/myeloma → skull & dura
- Pelvic/colonic tumours → posterior fossa
- Renal cell / melanoma → haemorrhagic secondaries
🩺 Clinical Features
- Headache, nausea/vomiting (raised ICP, oedema).
- Seizures (new-onset seizure in adult = red flag 🚨).
- Focal deficits: weakness, speech disturbance, visual field loss.
- Cerebellar involvement → ataxia, nystagmus.
- Stroke-like presentation (ischaemic/haemorrhagic mimic).
🧪 Investigations
- MRI (gold standard): Multiple circumscribed lesions with vasogenic oedema; better than CT for posterior fossa.
- CT with contrast: Detects most >1 cm lesions, useful acutely.
- Solitary lesion: Always consider a primary brain tumour until proven otherwise.
🔍 Searching for a Primary
- Skin exam → melanoma.
- Thyroid palpation/USS.
- Breast exam ± mammography.
- CT chest/abdomen/pelvis → lung, renal, GI primaries.
- Tumour markers: CEA, LFTs.
- Bone scan for skeletal metastases.
- GI endoscopy if indicated.
💊 Management
- Depends on number of lesions, systemic disease burden, and performance status.
- Corticosteroids: Dexamethasone rapidly reduces oedema & improves symptoms 🎯.
- Anticonvulsants: Levetiracetam preferred for seizure prophylaxis.
- Surgery: For solitary, accessible lesions in good surgical candidates.
- Radiotherapy: Whole-brain radiotherapy (WBRT) for multiple lesions; stereotactic radiosurgery (SRS) for limited deposits.
- Chemotherapy: Limited CNS penetration but used in sensitive primaries (e.g. germ cell tumours, small cell lung cancer).
- MDT input (neurosurgery, oncology, palliative care) is essential for individualized treatment planning.
📈 Prognosis
- Median survival historically 3–6 months; improved with SRS and modern therapies.
- Best prognosis: solitary metastasis, controlled primary, good performance status.
- End-of-life care is an important consideration in advanced systemic disease.
