Low-grade astrocytomas are made up of the least aggressive cancer cells. These are usually slow growing and noninvasive or have a slow rate of infiltration. High-grade astrocytomas infiltrate surrounding tissues and frequently involve both hemispheres of the brain. The most important prognostic factors in patients with high-grade astrocytomas are the characteristics of the cancer cells, age and overall health of the patient, duration and type of symptoms, and how much of the tumor and cancer cells can be removed. Surgery alone may give a patient several additional months of life.
Most studies suggest that removing all or most of the tumor can prolong life for some patients.
Pilocytic astrocytoma - The most common noninfiltrative astrocytomas are pilocytic astrocytomas, which are well defined, rarely transform, and are able to be removed surgically. They occur more commonly in the cerebellum of children but also develop in the cerebral cortex of adults. This tumor type is also known as a Grade 4 astrocytoma. It is the most malignant form of astrocytoma, a rapidly growing, diffusely infiltrating tumor. Mixed oligoastrocytoma generally has a better prognosis than diffuse astrocytoma.