Brain metastases

Definition:

• Brain metastases are cancerous growths that have spread (metastasized) to the brain from primary tumors elsewhere in the body.

Epidemiology:

• More common than primary brain tumors.
• Often seen in patients with advanced systemic cancer, particularly lung cancer, breast cancer, melanoma, renal cell carcinoma, and colorectal cancer.

Pathophysiology:

• Cancer cells spread via the bloodstream or lymphatic system to the brain, where they grow and form secondary tumors.
• Tend to be located at the junction between gray and white matter.

Clinical Features:

• Symptoms depend on the location and size of the metastases but can include headaches, seizures, neurological deficits (e.g., weakness, numbness), and cognitive or behavioral changes.
• Increased intracranial pressure can cause nausea, vomiting, and altered consciousness.

Diagnosis:

• MRI with contrast is the preferred imaging modality for detection and characterization of brain metastases.
• Whole-body imaging (e.g., PET-CT) to identify primary tumor and other metastases.
• Biopsy for histological confirmation, if the primary cancer is unknown.

Management:

• Treatment depends on the number of lesions, the type of primary cancer, the patient’s overall health, and symptoms.
• Options include:
  • Surgical resection for accessible single lesions.
  • Radiation therapy, including whole-brain radiation therapy (WBRT) or stereotactic radiosurgery (SRS).
  • Systemic therapy based on the primary cancer type (e.g., chemotherapy, targeted therapy, immunotherapy).
• Symptomatic treatment for edema (e.g., corticosteroids) and seizures (antiepileptic drugs).