Glioma’s

Tumor Types: Glial Tumors (Gliomas)

• Astrocytoma
• Pilocytic Astrocytoma
• Low-grade Astrocytoma
• Anaplastic Astrocytoma
• Glioblastoma Multiforme

There are two types of cells that make up the nervous system: neurons and neuroglia. Neurons send and receive nerve messages. Neuroglia, otherwise known as glial cells, often surround the neurons. Glial cells play a supportive role by nourishing, protecting and supporting neurons. There are six kinds of glial cells; oligodendrocytes, astrocytes, ependymal cells, Schwann cells, microglia, and satellite cells.

A brain tumor that develops from glial cells is called a glioma. About half of all primary brain tumors and one-fifth of all primary spinal cord tumors form from glial cells. Gliomas tend to grow in the cerebral hemispheres, but may also occur in the brain stem, optic nerves, spinal cord, and cerebellum. Gliomas are divided into subgroups depending on the origin of the glial cells. The most common type of glioma is an astrocytoma.

 
Astrocytoma

An astrocytoma develops from star-shaped glial cells (astrocytes) that support nerve cells. These tumors can be located anywhere in the brain, but the most common location is in the frontal lobe. Astrocytomas are the most common primary CNS tumor.
The physician, usually the neurosurgeon or neuro-oncologist, will discuss the type and location of an astrocytoma. The pathologist will assign it a grade. Astrocytomas are generally classified as low or high grade. Low-grade astrocytomas are slow growing. High-grade astrocytomas (grades three and four) grow more quickly. The main tumor type is listed for each grade. There are additional tumor types in each of these grades.

The WHO classification divides astrocytomas into four grades:

• Grade I, Pilocytic Astrocytoma
• Grade II, Low-Grade Astrocytoma
• Grade III, Anaplastic Astrocytoma
• Grade IV, Glioblastoma Multiforme (GBM or Glioblastoma)

Characteristics

The characteristics of an astrocytoma vary depending on the tumor's grade and location. Most people are functioning normally when diagnosed with a low-grade astrocytoma. Symptoms tend to be subtle and may take one to two years to diagnose. This is because the brain can often adapt to a slow-growing tumor for a period of time. High-grade tumors may present with changes that are sudden and dramatic.

Symptoms

• Headaches
• Seizures or convulsions
• Difficulty thinking or speaking
• Behavioral or cognitive changes (related to thinking, reasoning, and memory)
• Weakness or paralysis in one part or one side of the body
• Loss of balance
• Vision changes
• Nausea or vomiting

Pilocytic Astrocytoma (Grade I)

Also called a Juvenile Pilocytic Astrocytoma (JPA)

Characteristics

• Slow growing, with relatively well-defined borders
• Grows in the cerebrum, optic nerve pathways, brain stem and cerebellum
• Occurs most often in children and teens
• Accounts for two percent of all brain tumors
  

Treatment
Surgery is the standard treatment. If the tumor cannot be completely resected, radiation or chemotherapy may be given. Chemotherapy may be given to very young children instead of radiation therapy to avoid damage to the developing brain. Some of these tumors can progress to a higher grade, so it is important to be diligent about following up with the medical team after treatment.

Low-Grade Astrocytoma (Grade II)

Characteristics

• Slow growing
• Rarely spreads to other parts of the CNS
• Borders not well defined
• Common among men and women in their 20s-50s

Treatment

Treatment depends on the size and location of the tumor. The doctor will most likely perform a biopsy or surgery to remove the tumor. Partial resections or inoperable tumors may be treated with radiation. Recurring tumors may require additional surgery, radiation and/or chemotherapy.

Anaplastic Astrocytoma (Grade III)

Characteristics

• Grows faster and more aggressively than grade II astrocytomas
• Tumor cells are not uniform in appearance
• Invades neighboring tissue
• Common among men and women in their 30s-50s
• More common in men than women
• Accounts for four percent of all brain tumors

Treatment

Treatment depends on the location of the tumor and how far it has progressed. Surgery and radiation therapy, with chemotherapy during or following radiation, are the standard treatments. If surgery is not an option, then the doctor may recommend radiation and/or chemotherapy. Many clinical trials (experimental treatments) using radiation, chemotherapy, or a combination are available for initial and recurrent anaplastic astrocytomas.

Glioblastoma Multiforme (GBM ) (Grade IV )

Characteristics

• Most invasive type of glial tumor
• Commonly spreads to nearby tissue
• Grows rapidly
• May be composed of several different kinds of cells (i.e., astrocytes, oligodendrocytes)
• May have evolved from a low-grade astrocytoma or an oligodendroglioma
• Common among men and women in their 50s-70s
• More common in men than women
• Accounts for 23 percent of all primary brain tumors

Treatment

Standard treatment is surgery followed by radiation therapy or a combination of radiation therapy and chemotherapy. If surgery is not an option, the doctor may administer radiation therapy followed by or in conjunction with chemotherapy. Many clinical trials (experimental treatments) using radiation, chemotherapy, or a combination are available for initial and recurrent GBM. Clinical trials using molecularly targeted therapies showing success in other cancers are also being tested in GBM patients.