18 Multiple Brain Metastases

Case 18 Multiple Brain Metastases

Ramez Malak and Robert Moumdjian

Fig. 18.1 (A,B) Computed tomography (CT) scans of the head with contrast brain windows.

Fig. 18.2 T1-weighted magnetic resonance image (MRI) of the brain with contrast, axial section.

Clinical Presentation

A 63-year-old woman presents with history of breast cancer treated successfully a year ago.
She presents with progressive fatigue, drowsiness, and downward gaze for the last 3 weeks.
Neurologic examination reveals no lateralization or localization.

Questions

Describe the computed tomography (CT) scan (Fig. 18.1).
What is your initial workup?
A magnetic resonance imaging (MRI) scan was ordered and revealed more than 10 lesions. Give the differential diagnosis of multiple cerebral lesions (Fig. 18.2).
What are the indications for biopsy?
What are the indications for aggressive treatment with surgery or radiosurgery?
What are the factors in favor of surgery over radiosurgery?
Describe some adjuvant therapies.
What is the prognosis?

Answers

Describe the CT scan (Fig. 18.1).
- Multiple lesions in the brain parenchyma are visualized (at least four lesions)
  - Left frontal precoronal cortico-subcortical round enhancing lesion with associated edema
  - Right frontal edema, no lesion seen
  - Left thalamic enhancing lesion with compression of the 3rd ventricle and moderate hydrocephalus with cerebrospinal transependymal transudation
  - Left occipital periventricular enhancing lesion
What is your initial workup?
- Metastatic workup
  - If primary is unknown or controlled for a long time
  - CT scan of the chest, abdomen, and pelvis
  - Radionuclide bone scan
  - Tumor markers (serum, cerebrospinal fluid)
- Brain MRI with contrast and spectroscopy
- Total body positron emission tomography scan
An MRI was ordered and revealed more than 10 lesions. Give the differential diagnosis of multiple cerebral lesions (Fig. 18.2).
- Table 18.1¹
What are the indications for biopsy?
- Unknown primary (10% of brain metastasis have no primary)
- Remote history of systemic cancer
- To rule out radiation necrosis in patients previously treated with radiation to the brain
- Unusual appearing lesions, or unusual clinical presentation such as fever in a patient with known cancer²
What are the indications for aggressive treatment with surgery or radiosurgery?
- Primary control
- Expected relatively long disease-free interval
- Karnofsky performance score (KPS) of 70 or greater
- Young age (age is a predictor of survival length)
- Absence of leptomeningeal involvement
- Fewer than four brain metastases (the probability of tumor control is 64% for one tumor, 51% for two, and 41% for three lesions).³
What are the factors in favor of surgery over radiosurgery?
- Factors favoring surgery^2,4
  - Surgical accessibility
  - Undiagnosed primary
  - Need for immediate tumor debulking (rapid deterioration due to mass effect)
  - A lesion that is causing hydrocephalus
  - Rapid weaning of steroids
  - Lesions unlikely to respond to radiation
  - Radiation resistant tumors (thyroid carcinoma, renal cell carcinoma, and melanoma)
  - Highly cystic tumors
  - Very large tumors (>3 cm)
- Factors favoring radiosurgery²
  - To avoid the need for multiple craniotomies
  - Associated morbidities (prior general status)
  - Surgery is usually not indicated for the following brain metastases
    - Small cell cancer of the lung
    - Germ cell tumors
    - Multiple myeloma
    - Leukemia and lymphoma
Describe some adjuvant therapies.
- Patients with poor (low) KPS scores and progressive systemic disease often receive WBRT alone.
- Current radiation doses are either 20 Gy in five fractions or 30 Gy in 10 fractions.
- In patients with longer life expectancy (i.e., 1 year or more), a prolonged fractionation regimen of 40 Gy in 2-Gy fractions may decrease radiation-induced morbidity.
- The combination of WBRT and surgery or stereotactic radiosurgery for the treatment of patients with two to four tumors significantly improves the control of brain disease.⁵
What is the prognosis?
- If no treatment is given, survival can be as little as 4 weeks.
- When the patient is taking high-dose glucocorticoids survival increases to 8 weeks.
- WBRT can improve survival to 3 to 6 months.²
- The addition of either tumor resection or SRS in a subset of these patients is associated with improved outcome.^3,6–9 Survival was similar to a matched control group of patients with single metastases (average 14-month).⁶
- Patients with four or more brain metastases continue to have a particularly poor prognosis and are usually not treated surgically.⁴