These tumors originate within star-shaped brain cells called astrocytes. These cells form the brain’s supportive structure. Astrocytomas can develop throughout the brain, and, less commonly, in the spinal cord.
How a Tumor Forms
Tumors result from a problem with the genetic code that regulates the growth and division of the body’s cells. This code can become damaged because of an inherited flaw, a virus or an environmental trigger. Once it is damaged, the cell can grow and divide abnormally. A tumor is a lump of these abnormal cells.
Types of Astrocytomas
There are several different types of astrocytomas. They range from slow-growing to aggressive. They are classified depending on their characteristics. Some organizations use a three-tiered system. In this system, astrocytomas are classified as low, intermediate or high grade. Low grade astrocytomas are the slowest growing, and high grade astrocytomas are the most aggressive. Other organizations rank astrocytomas on a four-tiered scale. In this system, astrocytomas are given a grade of I to IV.
Grade I astrocytomas are uncommon, accounting for only a small percentage of all brain tumors. These tumors usually grow very slowly and do not infiltrate surrounding brain tissue. They can, however, become very large. In many cases, they respond well to treatment.
Grade II astrocytomas are also slow growing tumors, but they are invasive and can infiltrate surrounding brain tissue. Many of these tumors can be treated, but the success depends on the tumor’s location within the brain. A grade II tumor that is not treated will most likely evolve into a more aggressive grade over time.
Grade III astrocytomas, also called anaplastic astrocytomas, are aggressive tumors that can infiltrate surrounding tissues. They grow more rapidly than grade II tumors. They can be difficult to treat.
Grade IV astrocytomas, also called glioblastomas (or GBMs), are the most common type of astrocytoma. They are also the most aggressive type. These tumors tend to penetrate the nearby healthy tissues and spread throughout the surrounding portion of the brain. They can be difficult to treat.
Symptoms of astrocytomas can vary greatly depending on the type, size and location of the tumor. They can affect the mind and body in many different ways. They can cause physical problems, such as severe headaches or nausea. They can cause seizures, weakness or numbness. They can also cause behavioral changes, such as confusion and impulsiveness.
Treatment options may include surgical removal, radiation therapy and chemotherapy. A patient’s treatment plan will depend on the aggressiveness of the tumor and its location within the brain. Treatment will also depend on the age, size and condition of the patient.