Secondary brain cancer. Coloured magnetic resonance imaging (MRI) scan of a human brain, showing a malignant (cancerous) brain tumour (blue, lower right) of the occipital lobe. The front of the head is at top showing the eyeballs (red). This is a secondary (metastatic) cancer as it has spread (metastasised) from the site of another cancer. Tumours put pressure on the brain, causing a range of symptoms. These depend on the area of the brain affected, but can include headaches, changes in behaviour, seizures and nausea and vomiting. Once a cancer has spread beyond its initial site the prognosis is poor. Treatment is with surgery to remove the tumour, or radiotherapy or immunotherapy to reduce its size.