Brain Metastases

Brain metastases are cancer deposits that spread to the brain from a cancer that began elsewhere in the body.

They are also called secondary brain tumours. Their cells retain features of the original cancer, so a deposit from lung cancer is treated as lung cancer that has spread, not as a cancer that started in brain tissue. A person may have one deposit or several in different brain areas.

Brain metastases often cause a persistent or changing headache, weakness on one side, balance trouble, nausea, confusion, speech or vision changes, or a first-time seizure. The pattern depends on a deposit's location, size and surrounding swelling. Symptoms can develop gradually or appear suddenly.

Call emergency services for a first seizure, prolonged or repeated seizures, sudden weakness, new severe confusion, loss of consciousness or an abrupt intense headache. Keep someone having a seizure away from hazards, cushion the head, do not restrain them and put nothing in their mouth.

Cancer cells can detach from a primary tumour, travel through the bloodstream and settle in brain tissue. Lung cancer, breast cancer and melanoma are among the cancers that can spread this way, although other cancer types can also do so. Brain metastases are not contagious and are not caused by everyday activities.

A deposit may grow and cause swelling in nearby tissue, disturbing the function controlled by that brain region. Doctors consider the number, size and location of deposits, the behaviour of the original cancer, disease elsewhere in the body and the person's general condition. These factors guide whether treatment focuses on local control, whole-brain treatment, systemic therapy or symptom relief.

The main risk is having a cancer type and biological subtype capable of spreading to the brain, especially when cancer is advanced or active elsewhere. Risk differs between individuals and can change during the illness. New neurological symptoms need assessment based on their urgency; they should not be interpreted from risk factors alone.

Neurological examination checks strength, sensation, coordination, vision, speech and thinking. Contrast-enhanced MRI usually gives detailed images of the deposits and surrounding swelling; CT can be useful when rapid imaging is needed or MRI is unsuitable. Scans of the body help assess the original cancer and disease elsewhere.

If the primary cancer is unknown or imaging is uncertain, surgery or biopsy may provide tissue for diagnosis. Pathology and molecular testing can show where the cancer began and whether a targeted medicine might be relevant.

Steroids can reduce swelling and ease pressure-related symptoms; the dose is then adjusted carefully by the clinical team. Anti-seizure medicine is used when indicated. Stereotactic radiosurgery delivers focused radiation to selected deposits, while whole brain radiotherapy treats a broader area when disease is more widespread.

Brain tumour surgery may remove an accessible deposit that is causing pressure, establish a diagnosis or provide rapid symptom relief. Some targeted therapies, immunotherapies or chemotherapy can control deposits when the original cancer is sensitive to them. The plan may combine approaches and should reflect likely benefit, side effects and personal goals.

Until the treating team advises otherwise, avoid driving and activities where a seizure or sudden loss of control could cause serious harm. Occupational therapy, physiotherapy and speech therapy can support independence. Keep an up-to-date medicine list, take steroids exactly as directed and never stop them suddenly unless the prescriber provides a tapering plan. Palliative care can help manage symptoms alongside cancer treatment at any stage.