Makindo Medical Notes

Related Subjects: |Hypercalcaemia |Neutropenic Sepsis |Pulmonary Embolism |Superior vena caval obstruction syndrome |Cerebral Metastases |Metastatic bone disease |Oncological emergencies

Whole brain radiation treatment is the primary treatment.

About

• Lung cancer is the most common cause of brain metastases.

Aetiology

• Brain metastases are typically found at the junction between grey and white matter.
• They are more frequent in border zones between the middle cerebral artery (MCA) and posterior cerebral artery (PCA).
• Most common primary sources: carcinomas and malignant melanomas.
• 80% occur in the cerebral hemispheres, and 20% are subtentorial (below the tentorium cerebelli).

Common Primary Tumours Causing Brain Metastases

• Lung cancer
• Breast cancer (intraductal type often metastasizes to the cerebellum)
• Testicular cancer
• Renal cell carcinoma
• Malignant melanoma
• Colon, ovary, prostate, and thyroid cancers

Rarely Associated with Brain Metastases

• Prostate cancer
• Ovarian cancer
• Hodgkin's disease

Location of Metastases

• Breast, prostate cancers, and myeloma may metastasize to the skull and dura.
• Pelvic and colonic tumours tend to metastasize to the posterior fossa.

Haemorrhagic Metastases

• Melanoma
• Choriocarcinoma
• Lung cancer
• Thyroid cancer
• Kidney cancer

Clinical Presentation

• Seizures, headaches, and weakness (see Brain Tumour section for more details).
• Cerebellar lesions may present with ataxia.
• Stroke-like presentations (either ischaemic or haemorrhagic).

Investigations

• CT/MRI: Brain metastases typically present as circumscribed solid or ring-shaped lesions with surrounding vasogenic oedema.
• CT with contrast: Detects most lesions greater than 1 cm. MRI is more sensitive, particularly for detecting lesions in the posterior fossa.
• Solitary lesions should always prompt investigation to rule out a primary brain tumour.

Finding a Primary Tumour

• Examine the skin for melanoma.
• Examine the thyroid for masses.
• Breast examination for lumps or masses.
• CT scans of the chest, abdomen, and pelvis to detect primary tumours.
• Tumour markers: CEA, LFTs.
• Bone scan for metastasis.
• Mammography for breast cancer.
• Upper and lower GI endoscopy for gastrointestinal primary tumours.

Management

• Management depends on the extent of the metastases, presence of disease elsewhere, and the patient's comorbidities.
• Solitary metastases may be treated with resection, radiation, or a combination of treatments.
• Steroids: Dexamethasone is commonly given to reduce oedema, often providing dramatic short-term improvement.
• Anticonvulsants: Levetiracetam may be used for patients with seizures or those at high risk of seizures.
• After imaging (CT or MRI), discuss with neurosurgeons for potential biopsy and tissue diagnosis, as well as decisions regarding further treatment.
• Treatment options may include surgery, chemotherapy, or whole brain irradiation.