What Is Brain/CNS Cancer?
The central nervous system (CNS) is the medical name for the brain and spinal cord. Brain/CNS tumors are masses of abnormal cells in these areas that have grown out of control. There are two types of tumors. Primary tumors start in the brain/CNS and can be benign (non-cancerous) or malignant (cancerous). Metastatic tumors start in other parts of the body, most often the lungs, breast and colon, and spread (metastasize) to the brain/CNS. They are always malignant.
Most primary brain tumors can spread through the brain, but rarely spread to other areas of the body. However, even if a primary brain tumor is benign it presents a significant risk. As tumors grow they can compress normal brain tissue causing damage that can be disabling or even fatal. For this reason, physicians often speak of brain “tumors” and not brain “cancer.” The main concern with brain tumors is how quickly they spread to other parts of the CNS and how thoroughly they can be removed.
The four major categories of brain tumors include:
- Metastatic – the spread of cancer from one organ or part of the body to the brain and central nervous system.
- Gliomas - which occur in the glial cells that help support and protect critical areas of the brain. About 4 in 10 brain tumors are gliomas (includes benign and malignant tumors).
- Meningiomas – which are slow growing tumors that affect the meninges—the tissue that forms the protective outer covering of the brain. Twenty-five percent of all brain/CNS tumors are meningiomas and up to 85% of them are benign. They don’t typically produce symptoms, but if detected can be successfully treated with surgery.
- Schwannomas – which occur in the sheath that covers nerve cells. Vestibular schwannomas, (also known as acoustic neuromas) are responsible for hearing. These are typically benign and respond well to surgery.
- Medulloblastomas - which are common brain tumors in children. They grow quickly, and invade neighboring parts of the brain and CNS.