Makindo Medical Notes

🌐 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.