Adult Brain Tumors

by National Cancer Institute

What are adult brain tumors?

Adult brain tumors are diseases in which cancer (malignant) cells begin to grow in the tissues of the brain. The brain controls memory and learning, senses (hearing, sight, smell, taste, and touch), and emotion. It also controls other parts of the body, including muscles, organs, and blood vessels. Tumors that start in the brain are called primary brain tumors.

What are metastatic brain tumors?

Often, tumors found in the brain have started somewhere else in the body and spread (metastasized) to the brain. These are called metastatic brain tumors.

What are the symptoms of an adult brain tumor?

A doctor should be seen if the following symptoms appear:

• Frequent headaches.
• Vomiting.
• Loss of appetite.
• Changes in mood and personality.
• Changes in ability to think and learn.
• Seizures.

What tests are used to find and diagnose adult brain tumors?

Tests that examine the brain and spinal cord are used to detect (find) adult brain tumor. The following tests and procedures may be used:

CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.

MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of the brain and spinal cord. A substance called gadolinium is injected into the patient through a vein. The gadolinium collects around the cancer cells so they show up brighter in the picture. This procedure is also called nuclear magnetic resonance imaging (NMRI).

Adult brain tumor is diagnosed and removed in surgery. If a brain tumor is suspected, a biopsy is done by removing part of the skull and using a needle to remove a sample of the brain tissue. A pathologist views the tissue under a microscope to look for cancer cells. If cancer cells are found, the doctor will remove as much tumor as safely possible during the same surgery. An MRI may then be done to determine if any cancer cells remain after surgery. Tests are also done to find out the grade of the tumor.

What is the grade of a tumor?

The grade of a tumor refers to how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread. The pathologist determines the grade of the tumor using tissue removed for biopsy. The following grading system may be used for adult brain tumors:

Grade I

The tumor grows slowly, has cells that look similar to normal cells, and rarely spreads into nearby tissues. It may be possible to remove the entire tumor by surgery.

Grade II

The tumor grows slowly, but may spread into nearby tissue and may become a higher-grade tumor.

Grade III

The tumor grows quickly, is likely to spread into nearby tissue, and the tumor cells look very different from normal cells.

Grade IV

The tumor grows very aggressively, has cells that look very different from normal cells, and is difficult to treat successfully.

The chance of recovery (prognosis) and choice of treatment depend on the type, grade, and location of the tumor and whether cancer cells remain after surgery and/or have spread to other parts of the brain.

Types of Adult Brain Tumor

The extent or spread of cancer is usually described as stages. There is no standard staging system for brain tumors. Primary brain tumors may spread within the central nervous system (brain and spinal cord), but they rarely spread to other parts of the body. For treatment, brain tumors are classified by the type of cell in which the tumor began, the location of the tumor in the central nervous system, and the grade of the tumor.

Types of adult brain tumors include the following:

Brain Stem Gliomas

These are tumors that form in the brain stem, the part of the brain connected to the spinal cord. They are often high-grade. Brain stem gliomas that are high-grade or spread widely throughout the brain stem are difficult to treat successfully. To prevent damage to healthy brain tissue, brain stem glioma is usually diagnosed without a biopsy.

Pineal Astrocytic Tumor

Pineal tumors form in or near the pineal gland. The pineal gland is a tiny organ in the brain that produces the hormone melatonin, a substance that helps control our sleeping and waking cycle. There are several kinds of pineal tumors. Pineal astrocytic tumors are astrocytomas that occur in the pineal region and may be any grade.

Pilocytic Astrocytoma (grade I)

Astrocytomas are tumors that start in brain cells called astrocytes. Pilocytic astrocytomas grow slowly and rarely spread into the tissues around them. These tumors occur most often in children and young adults. They usually can be treated successfully.

Diffuse Astrocytoma (grade II)

Diffuse astrocytomas grow slowly, but they often spread into nearby tissues. Some of them progress to a higher grade. They occur most often in young adults.

Anaplastic Astrocytoma (grade III)

Anaplastic astrocytomas are also called malignant astrocytomas. They grow rapidly and spread into nearby tissues. The tumor cells look different from normal cells. The average age of patients developing anaplastic astrocytomas is 41 years.

Glioblastoma (grade IV)

Glioblastomas are malignant astrocytomas that grow and spread aggressively. The cells look very different from normal cells. Glioblastoma is also called glioblastoma multiforme or grade IV astrocytoma. They occur most often in adults between the ages of 45 and 70 years.

Refer to the following PDQ summaries for more information on astrocytomas:

• Childhood Cerebral Astrocytoma/Malignant Glioma Treatment
• Childhood Cerebellar Astrocytoma Treatment
• Childhood Visual Pathway and Hypothalamic Glioma Treatment

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