What is a glioma?
A glioma is a brain or spinal cord tumor that originates in the glial cells that surround the nerve cells. Approximately 80 percent of malignant (cancerous) tumors are gliomas.
Types of gliomas
There are three types of gliomas, which are named according to the brain cell they affect — astrocytomas, oligodendrogliomas and ependymomas.
Astrocytomas are the most common brain tumors, and they originate in the astrocyte cells.
A glioblastoma is a type of malignant astrocytoma.
Oligodendrogliomas tumors originate in the oligodendrocyte cells. Oligodendrocyte cells are only located in the body’s central nervous system (brain and spinal cord).
Ependymomas are a type of malignant brain tumor that is more common in children. This type of tumor originates in the ependymal cells and comprises 2 percent of all brain tumors.
Causes of gliomas
Although the exact cause of gliomas is unknown, some researchers have connected certain hereditary conditions to the condition.
Risk factors for gliomas
Factors that increase your likelihood of developing a glioma include:
- Gender — males are at higher risk for developing gliomas.
- Age — you are at higher risk of developing a brain tumor as you age; most brain tumors are diagnosed in adults ages 60 – 80.
- Heredity — you are at an increased risk of developing a glioma if a family member has also had a glioma.
- Radiation exposure — if you have been exposed to radiation from cancer treatment or an atomic bomb, you are at higher risk of developing a glioma.
Symptoms of gliomas
Although symptoms of gliomas will vary depending on where the tumor originates, the most common symptom is headache. Other symptoms that could indicate the presence of a glioma include:
- Memory loss
- Difficulty speaking clearly
- Unusual fatigue or weakness
- Changes in vision including loss of vision, blurred vision or double vision
- Unexplained irritability
As the condition progresses, your symptoms may intensify or change rapidly.
Diagnosing a glioma
Diagnosing a glioma is an extensive process that requires the expertise of a neurologist (a doctor who specializes in the brain and nervous system). During a neurology consult, your doctor will take a full medical history (including your family history), perform a physical exam and perform a neurological exam.
A neurological exam will check for problems in the brain and nervous system. During the exam, your doctor will check your vision, hearing, coordination, balance, strength, speech and memory.
After the neurological exam, your doctor may order diagnostic tests such as:
- Magnetic Resonance Imaging (MRI scan) — most commonly used diagnostic test to diagnose a brain tumor; during the exam, your doctor may inject dye into the veins to see the contrasting tissues more clearly.
- Computed tomography (CT scan) — another common diagnostic test that is used to diagnose a brain tumor; a CT scan will produce detailed images of the brain to determine the location and severity of the tumor.
- Biopsy — a biopsy of the brain tissue can determine if the tumor is benign or malignant; the results of the biopsy will identify the severity of your case and will be used to guide the treatment protocol.
Treatment of gliomas
Your doctor will develop a personalized treatment plan based on the grade and location of your tumor, type of glioma, your overall health and your treatment preferences.
Surgery is typically the first step in the treatment process. The primary goal of surgery is to remove as much of the tumor as possible without compromising brain function. Some tumors can be completely removed, while others may be in an area of the brain where complete removal is not possible. There is a high rate of tumor recurrence after surgery.
Radiation therapy typically is recommended after surgery for grades III and IV gliomas or for patients who are not candidates for surgery. Radiation therapy uses high-energy beams to destroy cancerous cells in the glioma. Types of radiation therapy used to treat gliomas include:
- External beam radiation — radiation therapy that originates from a machine outside of the body is external beam radiation. Your doctor will determine which external beam radiation treatment option is appropriate for your case.
- Stereotactic radiosurgery, such as Gamma Knife, uses targeted beams of radiation to kill cancerous cells in a small area.
- Internal radiation — internal radiation, also known as brachytherapy, is a radioactive substance that is implanted near the cancerous tumor site in the body. Brachytherapy can deliver a higher dose of radiation in a concentrated area than can be delivered via external radiation therapy.
- Chemotherapy — chemotherapy is a treatment for gliomas that used drugs, either injected or taken via pill, to kill cancerous glioma cells. Patients typically are treated with radiation therapy and chemotherapy simultaneously.
- Targeted drug therapy — targeted drug therapy is a new treatment option to kill cancerous cells in brain tumors. The drug works by killing proteins in cancerous cells and causing them to die. Avastin is one type of targeted drug therapy that is given intravenously.