Types of Brain Cancer
Cancer of the brain are abnormal growths of cells in the brain.
- Although such growths are popularly called brain tumors, not all brain tumors are cancer. Cancer is a term reserved for malignant tumors.
- Malignant tumors grow and spread aggressively, overpowering healthy cells by taking their space, blood, and nutrients. Like all cells of the body, tumor cells need blood and nutrients to survive.
- Tumors that do not spread aggressively are called benign.
- In general, a benign tumor is less serious than a malignant tumor. But a benign tumor can still cause many problems in the brain.
Primary Brain Cancers
The brain is made up of many different types of cells.
- Some brain cancers occur when one type of cell transforms from its normal characteristics. Once transformed, the cells grow and multiply in abnormal ways.
- As these abnormal cells grow, they become a mass, or tumor.
- The brain tumors that result are called primary brain tumors because they originate in the brain.
- The most common primary brain tumors are gliomas, meningiomas, pituitary adenomas, vestibular schwannomas, and primitive neuroectodermal tumors (medulloblastomas). The term glioma includes astrocytomas, oligodendrogliomas, and ependymomas.
- Most of these are named after the part of the brain or the type of brain cell from which they arise.
Metastatic Brain Cancer
Metastatic brain tumors are made of cancerous cells from a tumor elsewhere in the body. The cells spread to the brain from another tumor in a process called metastasis. About 25% of tumors elsewhere in the body metastasize to the brain.
In the U.S., brain tumors affect about one of every 5,000 people.
Causes of Brain Cancer
As with tumors elsewhere in the body, the exact cause of most brain cancer is unknown. Genetic factors, various environmental toxins, radiation, and cigarette smoking have all been linked to cancers of the brain. In most cases, no clear cause can be shown.
The following factors have been proposed as possible risk factors for primary brain tumors. Whether these factors actually increase your risk of a brain tumor is not known for sure.
- Radiation to the head
- Certain inherited conditions
- HIV infection
Brain Cancer Scans
MRI Brain Cancer Picture: Side view section through the brain of a young girl. The white arrow shows a brain tumor that involves the brainstem.
MRI Brain Cancer Picture: Cross-section (image taken from the top of the head down) of a brain tumor in a young girl. The white arrow shows the tumor.