(Brain Tumor; Glioma)
Astrocytoma – Definition
Astrocytoma is type of brain tumor. It is a malignant tumor, cancer. This type of tumor arises from small, star-shaped cells in the brain. They are called astrocytes. Astrocytes are one of several types of supporting cells in the brain. These type of cells are called glial cells. An astrocytoma is a subtype of the larger group of brain tumors called gliomas.
Astrocytoma is the most common form of glioma. It may occur anywhere in the brain. It is most commonly found in:
- The cerebrum in adults — the largest part of the brain
- The cerebellum — a smaller part of the brain in the rear
- Brainstem — connects to the spinal cord
- Optic nerves in children — nerve that leads from the brain to the eye
When an astrocytoma is diagnosed, the most important factors are:
- Grade of tumor (how aggressive it appears when viewed microscopically)
- Degree of neurological side effects produced by the tumor
- Age of the patient
These factors will determine the symptoms, prognosis, and treatment.
Astrocytoma – Causes
The exact cause is unknown. Some possible causes of brain tumors include:
- Certain occupations
- Environmental factors
Astrocytoma – Risk Factors
Although the exact risk factors for astrocytomas have not been identified, some studies suggest the following risk factors increase your chance of this tumor:
- Genetic disorders (including neurofibromatosis and tuberous sclerosis)
- Occupational exposure to:
- Oil refining
- Rubber manufacturing
Astrocytoma – Symptoms
The first symptoms of any brain tumor can be caused as the tumor grows. The growth can increase pressure in the brain. Symptoms may include:
- Visual changes
- Personality changes
- Problems with memory, thinking, and concentration
- Problems with walking
Symptoms will vary, depending on the location of the tumor. For example:
- Frontal lobe — gradual changes in mood and personality, paralysis on one side of the body
- Temporal lobe — problems with coordination, speech, and memory
- Parietal lobe — problems with sensation, writing, or fine motor skills
- Cerebellum — problems with coordination and balance
- Occipital lobe — problems with vision, visual hallucinations
Astrocytoma – Diagnosis
The doctor will ask about your symptoms and medical history. A physical exam will be done. Tests may include:
- MRI scan —a test that uses magnetic waves to define the anatomy of the brain, the most sensitive and clearest way to define a brain tumor
- CT scan — an x-ray device that takes circular pictures of the brain using x-ray beams
- Angiogram — x-rays taken after a dye is injected into the arteries, allowing the doctor to look for abnormalities in the arteries that lead to the brain
- Biopsy/resection — removal of a sample of brain tissue to test for cancer cells
A specialist will determine the grade of the tumor. Astrocytomas are graded from I to IV. These grades indicate the prognosis and rate of tumor growth.
- Grades I and II—These low-grade astrocytomas grow slowly. They generally stay localized in an area of the brain. They are more commonly found in younger patients. Grade II astrocytomas can spread.
- Grades III and IV—These high-grade tumors grow rapidly. They can spread throughout the brain and spinal cord. Aggressive treatment is needed. This is the most common type found in adults. Grade III tumors are called anaplastic astrocytoma. Grade IV tumors are called glioblastoma multiforme or GBM.
Astrocytoma – Treatment
Treatment is based on the location, size, and grade of the tumor. Treatment may include:
Surgery involves the removal of as much of the tumor as possible. If the tumor is high grade, surgery will often be followed by radiation or chemotherapy to help prevent further spread.
Radiation Therapy (or Radiotherapy)
Radiation therapy involves the use of radiation to kill cancer cells or shrink the tumor. Radiation may be:
- External radiation therapy — radiation directed at the tumor from a source outside the body
- Internal radiation therapy (also called brachytherapy) — radioactive materials placed into the body near the cancer cells
Chemotherapy is the use of drugs to kill cancer cells. It may be given in many forms including pill, injection, and via a catheter (IV or port). The drugs enter the bloodstream. They travel through the body killing mostly cancer cells. Some healthy cells are killed as well.
Astrocytoma – Prevention
There are no guidelines because the exact cause is not known. It has been suggested that the electromagnetic waves emitted from high-tension wires or even cell phones may increase the risk of developing brain tumors. To date, there is no scientific evidence supporting this theory.