These are tumors that arise from star-shaped cells known as astrocytes. They make up the glue-like or supportive tissue of the brain.
They are graded on a scale of one to four based on how abnormal the cells look. There are low grade and high grade astrocytomas:
- Low grade astrocytomas: Usually localized and grow at a slow rate
- High grade astrocytomas: Grow rapidly and require a different course of treatment
Most astrocytomas that occur in children are low grade tumors. Whereas the majority of astrocytomas tumors that occur in adults are high grade.
What are the different grades of astrocytomas?
- Pilocytic Astrocytoma (Juvenile pilocytic astrocytomas): These are grade one astrocytomas that normally stay in the area in which they started and do not spread to other areas. This type is considered to be the most benign of all astrocytomas. There are two other types of grade one astrocytomas that are less well known. They are; cerebellar astrocytomas and desmoplastic infantile astrocytoma.
- Diffuse Astrocytomas (Astrocytomas grade two): These are grade two astrocytomas that tend to spread to surrounding tissue but grow at a relatively slow rate. This type includes fibrillary gemistocytic and protoplasmic astrocytoma.
- Anaplastic Astrocytoma: These are grade three tumors. They are rare and require more aggressive treatment than non-cancerous pilocytic astrocytoma.
- Astrocytoma Grade Four (Glioblastoma, previously called Gliobastoma Multiforme, Grade four Glioblastoma and GBM): The two types of astrocytomas grade four are primary, de novo and secondary. The primary tumors are very aggressive and they are the most common form of astrocytoma grade four. The secondary tumors are those that developed from lower grade tumors and evolved into a grade four tumor.
- Subependymal Giant Cell Astrocytoma: These are ventricular tumors associated with tuberculosis sclerosis.
SYMPTOMS OF ASTROCYTOMAS
Astrocytomas can cause signs and symptoms as they grow and press against your brain. They depend partly on how big and the location of your tumor.
What are the common early symptoms?
- Memory loss
- Changes in behaviour
TREATMENT OPTIONS AVAILABLE FOR ASTROCYTOMAS
Based on the type of astrocytoma you have, the location and how fast it is growing and your symptoms, your doctor will make a treatment plan with you.
- Surgery: The first step will most likely be the removal of the entire tumor or as much as possible. If the tumor is in the brain stem (an area where surgery is too risky), then surgery may not be possible. Surgery may be all it takes to cure grade one tumors. However, for higher grade tumors, surgery may not be able to remove the entire tumor.
- Radiation therapy: This is often given after surgery when the tumors couldn’t be completely or if the surgeons aren’t sure they removed the entire cancer.
- Chemotherapy: This is used before or after radiotherapy. It is often used for glioblastoma and anaplastic astrocytoma.
- Electric-field therapy: This therapy uses electrical fields to target cells in the tumor without compromising normal cells. Electrodes are placed directly on the scalp. This device is called Optune and it is given with chemotherapy after surgery and radiation. This therapy is FDA approved for both newly diagnosed patients and those who have recurring glioblastoma.
METHODS TO DIAGNOSE ASTROCYTOMA
- History taking and physical examination: Your doctor will ask you questions about your overall health, symptoms you have and family medical history, as those, who have a family history of cancers are assumed to be more predisposed to have the same condition. Then your doctor will perform a physical examination of your body to look for any visible symptoms.
- Computed tomography (CT or CAT scan): A three dimensional image of the inside of your body using X-rays taken from different angles is created. A computer will then combine these images into a detailed, cross-sectional view that will allow your doctor to spot any abnormalities or tumors. This can also be used to measure the size of the tumor. Sometimes, a contrast medium (special dye) is given before the scan so that the images are more detailed. This dye is injected into your vein or can be taken orally as a pill.
- Magnetic resonance imaging (MRI): Magnetic fields instead of X-rays are used to produce detailed images of the body. A contrast medium is also given before the scan so that the images created are clearer. This dye can be injected into your vein or taken orally as a pill.
- Biopsy: Even though other tests can suggest that a tumor is present, a biopsy is the only definite way to diagnose astrocytoma. A biopsy is performed to determine what type and grade of astrocytoma you may have. A neurosurgeon (a doctor who specializes in treating CNS tumor with surgery) will remove a small piece of tissue from the tumor. A pathologist (a doctor who specializes in interpreting lab tests to diagnose disease) will then examine the sample.