Your nervous system is made up of cells called neurons. Neurons are the functional cells of the nervous system; they conduct signals between different parts of your brain and body. However, your nervous system also contains a vast number of cells that nourish and support your neurons. These cells are called glial cells, and one important type of glial cell is an astrocyte—so named because of its star-shaped appearance.
An astrocytoma is a tumor that is made up of mutated or damaged astrocytes. When this happens, astrocytes cease to play a supportive role to your neurons and also lose their ability to grow in an organized and regulated way. This unchecked growth damages or destroys surrounding structures and is what causes the symptoms of an astrocytoma.
Astrocytomas are graded on a scale developed by the World Health Organization (WHO). The scale ranges from one (least aggressive) through four (most aggressive) depending on their microscopic characteristics:
- Grade I astrocytomas usually do not infiltrate or mix with surrounding tissues. Although they are slow growing, they can become quite large. The most common type of Grade I astrocytoma is called a pilocytic astrocytoma or juvenile pilocytic astrocytoma. Grade I astrocytomas are most common in children, teens, and young adults.
- Grade II astrocytomas are also sometimes called low grade or diffuse astrocytomas. Low-grade astrocytomas can infiltrate or mix with surrounding structures, and therefore their borders may not be clear on diagnostic images. They tend to grow slowly, and occur most often in adults between the ages of 20 and 40 years.
- Grade III astrocytomas are also known as anaplastic or malignant astrocytomas. They grow faster than Grade II astrocytomas and are more difficult to treat. They are most common in adults between the ages of 30 and 50 years.
- Grade IV astrocytomas are also called glioblastomas or glioblastoma multiforme (GBM). They grow the fastest of all astocytomas and always invade surrounding tissues. They are more common in men and most common in adults between the ages of 50 and 80 years. Learn more about glioblastoma multiforme (GBM).
Although magnetic resonance imaging (MRI) or other kinds of diagnostic scans can suggest what type of tumor you have, only a biopsy of tissue taken from the tumor can conclusively determine your tumor and its WHO classification.
How common are astrocytomas?
Astrocytomas are the most common tumors that originate in the brain and central nervous system. High-grade astrocytomas are much more common than low-grade astrocytomas.
Who gets astrocytomas?
Low-grade astrocytomas are more common in children, teens, and young adults.
High-grade astrocytomas (glioblastoma multiforme tumors) are more common in people over the age of 50.
How are astrocytomas diagnosed?
Magnetic resonance imaging (MRI) is the best method for locating a suspected brain tumor.
However, a completely definitive diagnosis of tumor type and grade cannot be made until a sample of your tumor is removed during a process called a biopsy. After the sample is removed, a specialist called a neuropathologist identifies the tumor using a microscope.
There are no blood tests that can diagnose an astrocytoma.
The symptoms of an astrocytoma depend on where the tumor is located and how large it has grown, but can include any of the following:
- Vision changes
- Weakness, difficulty walking, and coordination problems
- Cognitive impairment
Keep in mind that an astrocytoma cannot be diagnosed based on symptoms alone, and that only a medical professional can provide you with a definitive diagnosis.
Please seek the help of a medical professional if you are concerned about your health, and dial 9-1-1 if you are experiencing an emergency.
Your neurosurgeon and neuro-oncologist can help you decide on the best course of treatment based on the severity of your symptoms, the classification of your tumor, and where the tumor is located.
Surgery for Astrocytomas
The goal of surgery for an astrocytoma is to remove as much cancerous tissue as possible while preserving healthy structures. The infiltrative nature of astrocytomas—especially high grade astrocytomas—can make this challenging.
Barrow Neurological Institute at Dignity Health St. Joseph’s Hospital and Medical Center has been an early adopter of a surgical method that involves injection of a special dye that causes elements of the tumor to glow when placed under fluorescent lighting. We have found this method to greatly improve the total amount of the tumor that can be removed while causing minimal disruption to your neurological function.
Radiation Therapy for Astrocytomas
Gamma Knife and Cyberknife surgery are sometimes used alone or in conjunction with surgery and chemotherapy to treat an astrocytoma. These methods are less invasive than surgery and do not cause as many side effects as chemotherapy, but they take longer to shrink the tumor.
Chemotherapy for Astrocytomas
Some, but not all, astrocytomas respond to chemotherapy. Your neuro-oncologist will help you determine what role chemotherapy can play in your treatment.
- Date of last review: November 26, 2016