A brain tumor is a growth of unhealthy cells in the brain that is not normal. Tumors grow when the unhealthy cells multiply rapidly. Brain tumors may be benign (not cancer) or malignant (cancer). A tumor that is not cancer and does not spread to other parts of the body is called benign. A tumor that is cancer and can spread to other parts of the body is called malignant. Some tumors start in the brain. These are primary brain tumors. They may or may not be cancer. If a tumor starts somewhere else and spreads to the brain, it is a secondary brain tumor, or a metastasis. This kind of tumor is always cancer. Brain tumors may be different sizes. They can start small and grow bigger. The signs you may have depend on the size of the tumor and where it is located in your brain. Treatment for brain tumors depends on the size, location, and type of the tumor. The doctor can do surgery, chemo, or radiation therapy. Sometimes, these treatments are combined and used against the brain tumor.