Astrocytoma
(Brain Tumor; Glioma)
Definition
Astrocytoma is type of brain tumor. It is a malignant (cancerous) tumor. This type of tumor begins 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 types of cells are called glial cells. An astrocytoma is a type 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 the brain to the spinal cord
- Optic nerves in children—Nerve that leads from the brain to the eye
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When an astrocytoma is diagnosed, the most important factors are:
- Grade of tumor (how aggressive it looks under a microscope)
- Size
- Location
- Degree of side effects from the tumor
- Age of the patient
These factors will determine the symptoms, outlook, and treatment.
Causes
The exact cause is unknown. Some possible causes of brain tumors include:
- Heredity
- Certain occupations
- Environmental factors
- Viruses
Risk Factors
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:
- Radiation
- Chemicals
- Oil refining
- Rubber manufacturing
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:
- Headaches
- Visual changes
- Vomiting
- Seizures
- 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, loss of muscle function 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
Diagnosis
The doctor will ask about your symptoms and medical history. A physical exam will be done.
Your doctor may need to look at pictures of your brain. This can be done through:
You may also have biopsy/resection to remove a sample of brain tissue to test it for cancer cells.
Grading
A specialist will determine the grade of the tumor. Astrocytomas are graded from I to IV. These grades indicate the outlook and rate of tumor growth.
- Grades I and II—These low-grade astrocytomas grow slowly. They generally stay 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.
Treatment
Treatment is based on the location, size, and grade of the tumor. Treatment may include:
Surgery
Surgery involves the removal of as much of the tumor as possible. High grade tumors are treated with surgery. Surgery is 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 aimed 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
Chemotherapy
is the use of drugs to kill cancer cells. It may be given in many forms including pill, injection, and 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.
Prevention
There are no prevention guidelines because the exact cause of astrocytoma 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. There is no scientific evidence supporting this theory.
RESOURCES
American Brain Tumor Association http://www.abta.org/
American Cancer Society http://www.cancer.org
CANADIAN RESOURCES
Brain Tumor Foundation of Canada http://www.braintumour.ca/
Canadian Cancer Society http://www.cancer.ca/
References
Astrocytoma. EBSCO DynaMed website. Available at: https://dynamed.ebscohost.com/about/about-us. Updated December 7, 2011. Accessed November 8, 2012.
General information about adult brain tumors. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/pdq/treatment/adultbrain/HealthProfessional. Updated July 9, 2012. Accessed November 8, 2012.
