Brain cancer is a rare type of cancer. It is very rare for people to develop tumors on the brain, and of those, only 50% are malignant. Men are more likely to have a malignant tumor, whereas benign tumors and unknown diagnosis tumors are more common in women.

In case of a primary tumor, the origin is within the spinal cord or the brain itself. With a metastatic one, also known as a secondary tumor, the origin is a different type of cancer, elsewhere in the body, that has spread to the brain. Both of these types have a number of key other differences as well.

For most types of cancers there is a staging system to describe where a tumor is, whether it has spread, and whether it affects more parts of the body. However, the brain cancer prognosis and stages are slightly different, because it is rare for a brain tumor to spread.

Brain cancer treatments are very complex. This is because of the blood-brain barrier, which protects the spinal cord and brain from various chemicals found in the bloodstream. Unfortunately, this includes chemotherapy. Additionally, surgery of the brain is highly complex and it is easy for microscopic tumor pieces to be left behind.