Most brain tumors are named according to the type of cells from which they arise. Gliomas, which develop in the glial cells, are the most common type of primary brain tumor. Glial cells are not nerve cells (neurons), but rather provide support and protection for neurons in the brain and other parts of the nervous system.
Doctors categorize most brain tumors as being either high grade (rapidly growing) or low grade (slow-growing). Low-grade tumors are capable of growing and invading the brain, and can transform into high-grade tumors over time. Therefore, early diagnosis and monitoring is key to managing this type of tumor.
Types of Low-Grade Glioma
There are three types of low-grade glioma. Each is characterized according to the cells that make up the majority of the tumor:
- Low-grade astrocytoma: affects astrocytes, a type of glial cell
- Low-grade oligodendroglioma: affects glial cells called oligodendrocytes
- Mixed glioma: includes both astrocytes and oligodendrocytes
Recent research advances have allowed doctors to further classify these tumors by analyzing genes in the tumor tissue. This approach enables physicians to tailor treatment to a patient’s individual tumor and sometimes to help predict whether the tumor could become malignant.
We expect ongoing research at Memorial Sloan Kettering and other institutions to further refine this classification system, to benefit patients even more.
While there are a few genetic factors that may increase the risk of a brain tumor (such as neurofibromatosis and Li-Fraumeni disease) there are also several myths about the causes of brain tumors that are not supported by scientific research. For example, at this time there is no solid data that indicates the use of cell phones — or being exposed to the non-ionizing radiation these phones emit — will cause a brain tumor. Nor have experiencing a head injury, exposure to petrochemicals, or the consumption of aspartame been scientifically linked to an increased brain tumor risk.
Additional research is needed to determine any true environmental risk factors for brain tumors.
Talk with your doctor if you have any concerns about your risk of developing a brain tumor.
Symptoms of a low-grade glioma develop when a tumor destroys or compresses normal brain tissue, the tissues around the tumor swell, or the tumor interferes with the normal flow of fluid around the brain and spinal cord.
Because different parts of the brain are responsible for different functions of the body – such as movement, vision, and speech – symptoms of a low-grade glioma are usually related to a tumor’s location.
Symptoms of low-grade glioma may include:
- Headaches, which can be mild or happen in a pattern that is out of the ordinary for a particular person
- Seizures, which involve sudden, involuntary muscle movements
- Speech problems, including slow speech, difficulty finding words, substituting incorrect words when naming objects, or difficulties in understanding a conversation or a written text
- Weakness, often on one side of the body
- Imbalance or difficulty walking
- Impaired vision or a restricted field of vision
Symptoms of a brain tumor can often resemble those caused by other diseases. If you are experiencing any of the above symptoms, please consult your doctor.