Astrocytoma

Astrocytomas are tumors that develop in your central nervous system (CNS) that grow from star-shaped astrocyte cells. They usually develop in your brain but can develop in your spinal cord as well. Astrocytomas can be benign (noncancerous) or malignant (cancerous).

Astrocytes are glial cells (the type of cells that provide supportive tissue in your brain). Other glial cells include oligodendrocytes and ependymal cells. Astrocytoma is the most common glioma. A glioma is a tumor that forms when glial cells grow out of control.

Healthcare providers use grades to describe different types of astrocytomas. They don’t use a staging system as they do for many other types of cancer.

What are the types of astrocytoma?

Astrocytomas may be cancerous or noncancerous. The World Health Organization (WHO) categorizes astrocytomas into four grades. The grades depend on how fast astrocytomas grow and the likelihood that they’ll spread to (infiltrate) nearby brain tissue. Grade 1 astrocytomas are the mildest, while grade 4 astrocytomas are the most aggressive.

Noncancerous astrocytomas

Grade 1 astrocytomas, which are noncancerous, include:

• Pilocytic astrocytoma: This is a slow-growing tumor that doesn’t tend to spread. It’s the most common grade 1 astrocytoma. It’s benign and doesn’t require chemotherapy or radiation therapy after it’s surgically removed. Pilocytic astrocytomas most often develop in your cerebellum.
• Pleomorphic xanthoastrocytoma: This tumor usually grows slowly and most often develops in your temporal lobe. It often causes seizures. Surgery usually cures this type of brain tumor.
• Subependymal giant cell astrocytoma (SEGA): This tumor mainly develops in children who have tuberous sclerosis, a genetic condition. It grows inside ventricles, which are fluid-filled spaces deep in your brain. Surgery usually cures it.

Cancerous astrocytomas

Cancerous astrocytomas include:

• Grade 2 astrocytomas: These astrocytomas tend to spread to nearby brain tissue. Because of this, surgery alone might not be enough to treat them.
• Grade 3 astrocytomas: These astrocytomas are more aggressive than grade 2 astrocytomas and often present as a progression from grade 2 astrocytomas. Surgery alone never cures these tumors. They require radiation and almost always require chemotherapy.
• Glioblastomas: These are grade 4 astrocytomas. They’re the most common form of astrocytoma and the most aggressive — they grow and spread rapidly. They can either present as a cancerous progression from a previously existing lower-grade astrocytoma (10% of cases) or begin as a grade 4 tumor (90% of cases).

Who does astrocytoma affect?

Astrocytomas can affect anyone, but different grades tend to affect people at different ages:

• Grade 1 astrocytomas most often affect children and teens.
• Astrocytomas, grade 2 most often affect adults between 20 and 60.
• Astrocytomas, grade 3 most often affect adults between 30 and 60.
• Glioblastoma (grade 4 astrocytoma) most often affects adults between 50 and 80.

Grade 3 and 4 astrocytomas are more likely to affect adults assigned male at birth than adults assigned female at birth.

How common is astrocytoma?

Different grades of astrocytoma are more common than others:

• Grade 1 astrocytomas account for 2% of all brain tumors.
• Grade 2 astrocytomas account for 2% to 5% of all brain tumors.
• Grade 3 astrocytomas account for 4% of all brain tumors.
• Grade 4 astrocytomas (glioblastomas) account for 24% of all brain tumors.

In adults, glioblastoma (grade 4 astrocytoma) is the most common type of brain cancer.