Stages of Childhood Astrocytomas
Key Points for This Section
There is no standard staging system for childhood astrocytoma. Treatment is based on the grade of the tumor and whether it is untreated or recurrent (has come back after treatment). The grade of the tumor describes how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread.
The following grades are used:
Low-grade astrocytomas are slow-growing and rarely spread to other parts of the brain and spinal cord or other parts of the body. These include grade I (pilocytic, which form like a cyst and look almost like normal cells) and grade II (fibrillary, with cells that look long or slender like fibers) astrocytomas.
High-grade astrocytomas are fast-growing and often spread within the brain and spinal cord. These include grade III (anaplastic or malignant) and grade IV (glioblastoma, which spreads the fastest) astrocytomas.
Childhood astrocytomas may form at more than one place in the brain, but they do not usually spread to other parts of the body. Children who have neurofibromatosis type 1 are more likely to have tumors in more than one place.
Some of the tests used to detect astrocytomas are repeated after the tumor is removed. (See the General Information section.) This is to find out how much tumor remains after surgery and to plan further treatment. An MRI (magnetic resonance imaging) is done in the first 2 days after the surgery to see if there is any tumor left.
The three ways that cancer spreads in the body are:
- Through tissue. Cancer invades the surrounding normal tissue.
- Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
- Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.
When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.