Brain Metastases
Brain metastases are substantially more common than primary brain tumors and represent a significant proportion of patients with known—or occasionally undiagnosed—systemic malignancy. It is estimated that approximately 20–40% of patients with systemic cancer may develop symptomatic brain metastases.
Optimal management continues to evolve and typically requires an individualized strategy based on the number and size of lesions, symptoms and edema, the patient’s functional status, and the degree of control of the primary disease. The principal treatment “pillars” include surgical resection, whole-brain radiotherapy (WBRT), and stereotactic radiosurgery (SRS)—often in combination.
What are brain metastases?
They are secondary cancer deposits in the brain that originate from a malignancy elsewhere in the body.
Brain metastases occur when cells from a primary cancer (for example, lung or breast) spread through the bloodstream and establish within the brain. In contrast to many primary brain tumors, metastases are often more well-circumscribed, yet they can produce substantial vasogenic edema and mass effect on surrounding brain tissue.
How common are they and which primary cancers most often cause them?
In adults, brain metastases are approximately ten times more common than primary brain tumors.
In adult patients, the most frequent primary sources include:
- Lung cancer (the most common cause).
- Breast cancer.
- Melanoma.
The likelihood of developing brain metastases depends on tumor type, biological behavior, duration of disease, and response to systemic therapy.
What symptoms do they cause—and when should I be concerned?
Symptoms are driven by lesion location and by swelling (edema) in the surrounding brain.
Common clinical presentations:
- Headache (often worse in the morning, sometimes with nausea or progressive intensity).
- Seizures (especially with superficial/cortical lesions).
- Focal neurological deficits: weakness, numbness, speech disturbance, visual changes, balance impairment.
- Confusion, behavioral change, or decreased alertness in more severe situations.
Symptom severity does not always correlate with lesion size: smaller lesions in critical areas—or lesions with prominent edema—can be highly symptomatic.
How is the diagnosis made (MRI/CT), and what does “edema” mean?
Contrast-enhanced brain MRI is typically the reference standard, while CT is frequently used in urgent settings.
- Contrast-enhanced MRI: best for defining lesion number and morphology, surrounding edema, and proximity to eloquent brain regions.
- CT: valuable in emergencies (hemorrhage, hydrocephalus, significant edema).
Vasogenic edema around a metastasis is common and often explains a large portion of the symptoms. This is where corticosteroids may provide temporary relief while definitive therapy is arranged.
Which factors determine the treatment plan?
Treatment is chosen after assessing both intracranial disease and the broader oncologic context.
Key decision factors include:
- Number of lesions (solitary vs. multiple).
- Size and degree of edema (mass effect/midline shift).
- Location (superficial vs. deep; proximity to eloquent cortex/brainstem).
- Functional status and medical comorbidities.
- Control of the primary cancer and systemic disease burden.
- Histology/biology (e.g., hemorrhagic propensity; radiosensitivity).
When is surgical resection indicated and what are the goals?
Surgery provides the most rapid decompression and may be life-saving when edema and mass effect are severe.
Primary goals of surgery:
- Immediate decompression and neurological improvement when mass effect is present.
- Reduction of intracranial tumor burden and symptom control.
- Tissue diagnosis (histologic confirmation) in selected situations.
- Seizure control when medically refractory seizures are driven by the lesion.
When safe and feasible, en bloc resection may reduce local recurrence risk; however, the optimal technique is determined by lesion location, vascularity, and the neurological risk profile.
What is WBRT (whole-brain radiotherapy) and what are the pros/cons?
WBRT can treat visible lesions and microscopic disease, but it may affect cognitive function—particularly in long-term survivors.
WBRT has historically been a cornerstone therapy for multiple metastases or in situations with a high risk of developing new intracranial lesions. A key consideration, however, is the potential for neurocognitive effects, which must be balanced against expected benefit.
What is SRS (stereotactic radiosurgery) and when is it preferred?
SRS is high-precision focal radiation that delivers an ablative dose to the target while minimizing exposure to surrounding healthy brain.
Advantages:
- Non-invasive, often performed on an outpatient basis.
- High local control rates for appropriately selected lesions.
- Less global brain irradiation compared with WBRT.
Limitations:
- Larger lesions (often > ~3 cm) or lesions with substantial edema/mass effect may not be ideal candidates.
- Requires close surveillance for new lesions and timely salvage treatment when needed.
Combined strategies: Surgery + WBRT, SRS + WBRT, or SRS alone?
Treatment selection aims to balance oncologic control with preservation of neurological function and quality of life.
In selected scenarios, combination approaches may improve overall intracranial control but can increase treatment-related toxicity. Decisions are individualized and often consider:
- Solitary metastasis with edema/mass effect: often considered for surgical decompression followed by focal or adjuvant radiation.
- 1–4 lesions in a patient with good functional status: commonly managed with SRS-based strategies and structured follow-up.
- Multiple lesions or high risk of diffuse intracranial disease: WBRT may be discussed depending on overall goals and prognosis.
The “right” strategy is the one that aligns with the patient’s neurological risk, oncologic stage, anticipated trajectory, and personal priorities.
Supportive medications: corticosteroids & anti-seizure therapy—what to know
These medications do not “treat” the metastasis itself, but they can reduce symptoms (edema, seizures) and stabilize the patient while definitive therapy is planned.
Corticosteroids (e.g., dexamethasone)
- May provide temporary relief from symptoms related to edema and increased intracranial pressure.
- Dosing is individualized and typically followed by a careful taper when clinically appropriate.
Anti-seizure medications
- Indicated after a seizure or when clinical circumstances warrant treatment.
- Routine “prophylactic” use without a seizure history is not always necessary and is decided on a case-by-case basis.
Medication selection and duration consider interactions with systemic oncologic therapies and each agent’s adverse effect profile.
Systemic therapies (chemotherapy/targeted therapy/immunotherapy): what is their role?
Historically, conventional chemotherapy has been limited by the blood–brain barrier; however, modern oncologic therapies continue to expand available options for selected patients.
Many systemic agents have reduced penetration into the central nervous system. Nevertheless, in selected cases—depending on tumor biology and the oncology strategy—contemporary systemic therapies may contribute meaningfully to overall disease control.
Frequently asked questions & when to seek a second opinion
If there is only one metastasis, does surgery “cure” it?
Surgery can provide immediate decompression and excellent local control, but the overall plan often includes adjuvant focal radiotherapy and coordinated oncologic management of the systemic disease.
Does WBRT always cause memory problems?
Not always, but there is a real risk of cognitive effects depending on dose, age, baseline health, and overall survival. For this reason, when appropriate, we discuss alternatives such as SRS-based approaches that may better preserve cognitive function.
When do I need urgent evaluation?
- New or rapidly worsening weakness, speech disturbance, visual changes, or balance impairment.
- A seizure (or recurrent seizures).
- Signs of increased intracranial pressure: severe headache with nausea/vomiting, drowsiness, confusion.
Is SRS the same as “radiotherapy”?
SRS is a form of high-precision focal radiation that targets specific lesions with a high dose—often delivered in a single session or a small number of fractions—resulting in less exposure of the overall brain to radiation compared with WBRT.
At Neuroknife, evaluation is performed through integrated neurosurgical and oncologic collaboration, aiming for a realistic, safe, and individualized plan (surgery, SRS, WBRT, or combination therapy), with a focus on preserving neurological function and safeguarding quality of life.
When should you seek a specialized neurosurgical evaluation for brain metastases?
If there are new neurological symptoms, significant edema, seizures, or a lesion causing meaningful mass effect, timely neurosurgical assessment helps determine whether urgent decompression (surgery) or focal radiation (SRS) is indicated—and which pathway is safest.
An appropriate strategy may provide more rapid symptom improvement, better local control, and a smoother continuation of systemic oncologic treatment.
Schedule an Appointment or Request a Second Opinion© Neuroknife — Original medical content authored by our physicians, provided exclusively for patient education and information.