Brain Metastases - Gamma Knife Radiosurgery

Brain metastases are tumours formed by the spread of cancer from another organ to the brain. In fact, they are the most common type of brain tumour.¹ Today, with the advancement of cancer treatments, patients are living longer, which increases the incidence of brain metastases.

Which Cancers Metastasize to the Brain?

The cancers that most commonly metastasize to the brain are lung cancer, breast cancer, and melanoma.^2,3 Lung cancer is the type of cancer that metastasizes to the brain most frequently and earliest.

Symptoms and Diagnosis

The symptoms of brain metastases are similar to primary brain tumours: headache, seizures, focal neurological deficits, and cognitive changes. Contrast-enhanced brain MRI is the gold standard in diagnosis.⁴ Metastases are generally seen as well-circumscribed, round, contrast-enhancing lesions. Multiple lesions are a strong finding in favour of metastasis.

Surgical resection is preferred for single or a limited number of large, accessible metastases, and especially if there is a significant mass effect on the surrounding brain tissue.⁵

Treatment Options

The treatment strategy is determined based on the number, size, and location of the metastases, the control status of the primary cancer, and the patient's overall performance.

Surgical resection is preferred for single or a limited number of large, accessible metastases, and especially if there is a significant mass effect on the surrounding brain tissue. Surgery both confirms the pathological diagnosis and provides rapid symptom relief.

Gamma Knife radiosurgery is a revolutionary treatment method for brain metastases. Hundreds of fine gamma ray beams are focused on a single point, delivering a high dose of radiation to the tumour; the surrounding healthy tissue is preserved. It does not require surgery, is usually performed in a single session, and the patient can be discharged on the same day.

Gamma Knife generally provides a local control rate of around 80-90 percent in brain metastases.^6,7 Multiple metastases (up to 10-15 today) can be treated in a single session.^8,9

Whole brain radiotherapy (WBRT) is applied in the presence of numerous metastases or leptomeningeal spread.¹⁰ However, due to its side effects on cognitive functions, Gamma Knife or surgery is preferred whenever possible.^11,12

→ Next page: S15 — Metastasis Treatment Algorithm and Decision Tree