Brain Metastases

Background

• Brain metastases are a common neurological complication of systemic cancer in which metastases from a primary extracranial tumor invade the brain.
• Brain metastases occur in 8%-20% of patients with cancer, and are 10 times as common as primary brain tumors.
• The presence of brain metastases at the time of primary cancer diagnosis is reported in 1.7% of patients overall, and in 10%-15% of patients diagnosed with lung cancer.
• Brain metastases usually indicate limited life expectancy.
• "Limited brain metastases" refers to brain metastases in patients for whom stereotactic radiosurgery (SRS) is equally effective and offers significant cognitive protection compared to whole brain radiation therapy (WBRT).

Evaluation

• Brain metastases may be asymptomatic or have signs or symptoms similar to those of other mass lesions.
• Presentation of brain metastases include headache, seizure, motor deficits, hemisensory loss, personality changes, aphasia, visual disturbances, and symptoms of raised intracranial pressure.
• Suspect brain metastases in any patient with cancer who develops neurological signs or symptoms.
• Use magnetic resonance imaging (MRI) with and without contrast as the first-line imaging modality evaluate for brain metastases (Strong recommendation). Computed tomography (CT) with and without contrast can be used if MRI is not feasible.
• If there are suspected brain metastases on neuroimaging:
  • If the primary source is not known, conduct systematic diagnostic testing with chest x-ray or CT scan, abdominal or pelvic CT, or other tests as indicated (Strong recommendation). Also consider whole body imaging.
  • Surgery to investigate brain lesion can be considered for some patients.
    • Biopsy brain lesion to establish a diagnosis if no extracranial primary cancer is found or is accessible (Strong recommendation).
    • Also consider biopsy of brain lesion if the patient has a history of cancer or concerns regarding a correct diagnosis of brain lesion are present (Weak recommendation).
    • Consider resection of brain lesion if brain metastases are strongly suspected (history of cancer or if cancer is confirmed with extracranial tumor biopsy) plus either (Weak recommendation)
      • mass effect or other symptoms
      • limited brain metastases and systemic disease is newly diagnosed, stable, or has reasonable systemic treatment options.
• If the primary cancer is known, use all required primary cancer-specific assessments for staging to define primary cancer activity and extracranial metastases (Strong recommendation).
• Factors associated with a worse prognosis include:
  • older age
  • lower performance status
  • > 10 brain metastases
  • higher total volume of brain metastases
  • higher systemic tumor burden including uncontrolled systemic disease / primary tumor
  • systemic disease with relatively unfavorable histology

Management

• Assess the patient with a prognostic scoring system (preferably, the Graded Prognostic Assessment) before treatment (Strong recommendation).
• Consider supportive therapy, as appropriate, for all patients:
  • Corticosteroids if there are symptoms of edema or mass effect, antiseizure medications if there are seizures, or other medications as appropriate (Weak recommendation).
  • Symptom management for fatigue, depressive symptoms, declining sense of well-being or quality of life, or alterations in thought processes (Weak recommendation).
• For patients with limited brain metastases:
  • If newly diagnosed or stable systemic disease, consider stereotactic radiosurgery (SRS) (preferred) or whole brain radiation therapy (WBRT) (Weak recommendation).
  • Consider surgical resection (with subsequent radiation) for select patients (Weak recommendation):
    • to manage mass effect or other symptoms or if the lesion is > 3 cm and surgically accessible
    • systemic disease is newly diagnosed, stable, or has reasonable systemic treatment options
  • If disseminated systemic disease or poor prognosis, individualized options include (Weak recommendation)
    • WBRT or SRS
    • trial of central nervous system (CNS)-active systemic therapies
    • palliative / best supportive care
  • If secondary CNS lymphoma presents, consider systemic therapy and/or radiation (Weak recommendation).
  • For recurrent brain metastases, consider any treatment modality (including WBRT for large volume metastases if no prior WBRT) (Weak recommendation).
• For patients with extensive brain metastases:
  • Treat with either WBRT or SRS as the primary therapy (Strong recommendation).
  • If there is life-threatening mass effect, hemorrhage, or hydrocephalus, consider palliative surgical resection (Weak recommendation).
  • For recurrent brain metastases:
    • If systemic disease is stable or has reasonable systemic treatment options, consider surgical resection, SRS, WBRT (if no prior WBRT), or cancer-directed systemic therapy (Weak recommendation).
    • If there is systemic disease progression and there are limited treatment options, consider palliative/best supportive care (Weak recommendation).
• Also consider cancer-directed systemic therapy if the primary cancer is chemotherapy sensitive, such as with lung cancer, breast cancer, and melanoma (Weak recommendation).
• If brain lesion resection, perform postoperative brain MRI within 48 hours to determine the extent of the resection (Strong recommendation).
• Follow-up with brain MRI to assess progression and treatment effects (Strong recommendation):
  • every 2-3 months for 1-2 years and then every 4-6 months indefinitely
  • with any emergent signs or symptoms
  • consider every 2 months for patients with limited brain metastases treated with SRS alone or systemic therapy alone