Brain Metastases

Key Features

• Most common sources of intracranial metastasis

  • Lung cancer

  • Breast cancer

  • Skin cancer (melanoma)

  • Kidney cancer

  • GI tract cancer

• 10–15% of brain metastases are of unknown primary source

• Most common metastatic carcinomas to the leptomeninges are breast, lymphomas, and leukemia

Clinical Findings

• Intracranial metastases and primary cerebral neoplasms present similarly

  • Intracranial pressure

  • Focal or diffuse disturbance of cerebral function

• Leptomeningeal metastases cause

  • Multifocal neurologic deficits from infiltration of nerve roots

  • Direct invasion of the brain or spinal cord

  • Obstructive hydrocephalus

Diagnosis

• Laboratory and radiology studies are the same as for primary neoplasms

• Lumbar puncture is needed only if carcinomatous meningitis is suspected

  • Elevated cerebrospinal fluid pressure, pleocytosis, increased protein levels, and decreased glucose concentration are seen

  • Malignant cells may be found on cytology

• In leptomeningeal metastases, CT scans show contrast enhancement in the basal cisterns or hydrocephalus without any evidence of mass lesions

  • Gadolinium-enhanced MRI often shows leptomeningeal involvement

  • Myelography may show deposits on multiple nerve roots

Treatment

• A single cerebral metastasis may be irradiated, sometimes following surgical excision

• Systemic immunotherapy may also be an acceptable initial option in select cases

• Leptomeningeal metastases receive irradiation and intrathecal methotrexate

  • Prognosis is poor, with an approximately 10% survival at 1 year

  • Palliative care

• For multiple cerebral metastases or widespread systemic disease,

  • Stereotactic radiosurgery, whole-brain radiotherapy, or both, sometimes helps

  • Systemic chemotherapy or immunotherapy may be options

  • Otherwise, palliative care