Brain cancer refers to a malignant tumor that originates in the brain or spinal cord. It is a type of neoplasm, which means it is an abnormal growth of cells that have the ability to invade and damage surrounding tissues and organs. Brain cancers are classified according to the types of cells they start from (e.g., astrocytomas, gliomas, oligodendrogliomas) or by their behavior (e.g., benign or malignant). They can affect people of all ages but are more common in older adults. Treatment options for brain cancer include surgery, radiation therapy, chemotherapy, and targeted therapies, depending on the type and stage of the tumor.