Metastatic cancer occurs when cancer spreads from its original location (primary tumour) to a new part of the body.
Brain metastases occur when a cancer spreads to the brain from its primary site.
Brain metastases are different from a cancer that starts in the brain (called primary brain cancer).
Primary brain tumours occur much less often than brain metastases.
Brain metastases are fairly common in people with cancer.
It is estimated that 20–40% of intracranial tumours are metastatic.