Types of Brain and Spinal Cord Tumors in Adults
Tumors that start in the brain (primary brain tumors) are not the same as tumors that start in other organs, such as the lung or breast, and then spread to the brain (metastatic or secondary brain tumors). In adults, metastatic tumors to the brain are actually more common than primary brain tumors. These tumors are not treated the same way. For example, breast or lung cancers that spread to the brain are treated differently from tumors that start in the brain.
Unlike cancers that start in other parts of the body, tumors that start in the brain or spinal cord rarely spread to distant organs. Even so, brain or spinal cord tumors are rarely considered benign (non-cancerous). They can still cause damage by growing and spreading into nearby areas, where they can destroy normal brain tissue. And unless they are completely removed or destroyed, most brain or spinal cord tumors will continue to grow and eventually be life-threatening.
Brain and spinal cord tumor grades
Some brain and spinal cord tumors are more likely to grow into nearby tissues (and to grow quickly) than are other tumors. The World Health Organization (WHO) divides brain and spinal cord tumors into 4 grades (using Roman numerals I to IV), based largely on how the cells look under the microscope:
- Grade I: These tumors typically grow slowly and do not grow into (invade or infiltrate) nearby tissues. They can often be cured with surgery.
- Grade II: These tumors also tend to grow slowly but they can grow into nearby brain tissue. They are more likely to come back after surgery than grade I tumors. They are also more likely to become faster-growing tumors over time.
- Grade III: These tumors look more abnormal under the microscope. They can grow into nearby brain tissue and are more likely to need other treatments in addition to surgery.
- Grade IV: These are the fastest growing tumors. They generally require the most aggressive treatment.
Gliomas
Gliomas are not a specific type of brain tumor. Glioma is a general term for tumors that start in glial cells. A number of tumors can be considered gliomas, including:- Astrocytomas (which include glioblastomas)
- Oligodendrogliomas
- Ependymomas
About 3 out of 10 of all brain tumors are gliomas. Most fast-growing brain tumors are gliomas.Astrocytomas
Astrocytomas are tumors that start in glial cells called astrocytes. About 2 out of 10 brain tumors are astrocytomas.Most astrocytomas can spread widely throughout the brain and blend with the normal brain tissue, which can make them very hard to remove with surgery. Sometimes they spread along the cerebrospinal fluid (CSF) pathways. It is very rare for them to spread outside of the brain or spinal cord