Brain tumors involve the growth of abnormal cells in the tissues of the brain. Brain tumors can be benign (not cancer) or malignant (cancer).
Types of Primary Brain Tumors
There are many types of primary brain tumors. Primary brain tumors are named according to the type of cells or the part of the brain in which they begin. For example, most primary brain tumors begin in glial cells. This type of tumor is called a glioma.
Among adults, the most common types are:
Astrocytoma: The tumor arises from star-shaped glial cells called astrocytes. It can be any grade. In adults, an astrocytoma most often arises in the cerebrum.
Grade I or II astrocytoma: It may be called a low-grade glioma.
Grade III astrocytoma: It's sometimes called a high-grade or an anaplastic astrocytoma.
Grade IV astrocytoma: It may be called a glioblastoma or malignant astrocytic glioma.
Meningioma: The tumor arises in the meninges. It can be grade I, II, or III. It's usually benign (grade I) and grows slowly.
Oligodendroglioma: The tumor arises from cells that make the fatty substance that covers and protects nerves. It usually occurs in the cerebrum. It's most common in middle-aged adults. It can be grade II or III.
Among children, the most common types are:
Medulloblastoma: The tumor usually arises in the cerebellum. It's sometimes called a primitive neuroectodermal tumor. It is grade IV.
Grade I or II astrocytoma: In children, this lowgrade tumor occurs anywhere in the brain. The most common astrocytoma among children is juvenile pilocytic astrocytoma. It's grade I.
Ependymoma: The tumor arises from cells that line the ventricles or the central canal of the spinal cord. It's most commonly found in children and young adults. It can be grade I, II, or III.
Brain stem glioma: The tumor occurs in the lowest part of the brain. It can be a low-grade or high-grade tumor. The most common type is diffuse intrinsic pontine glioma .
You can find more information about types of brain tumors at http://www.cancer.gov/cancertopics/types/brain. Or, you can call the NCI Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).
Doctors group brain tumors by grade. The grade of a tumor refers to the way the cells look under a microscope:
Cells from low-grade tumors (grades I and II) look more normal and generally grow more slowly than cells from high-grade tumors (grades III and IV). Over time, a low-grade tumor may become a highgrade tumor. However, the change to a high-grade tumor happens more often among adults than children.
When you're told that you have a brain tumor, it's natural to wonder what may have caused your disease. But no one knows the exact causes of brain tumors. Doctors seldom know why one person develops a brain tumor and another doesn't. Researchers are studying whether people with certain risk factors are more likely than others to develop a brain tumor. A risk factor is something that may increase the chance of getting a disease. Studies have found the following risk factors for brain tumors:
Ionizing radiation: Ionizing radiation from high dose x-rays (such as radiation therapy from a large machine aimed at the head) and other sources can cause cell damage that leads to a tumor. People exposed to ionizing radiation may have an increased risk of a brain tumor, such as meningioma or glioma.
Family history: It is rare for brain tumors to run in a family. Only a very small number of families have several members with brain tumors.
Researchers are studying whether using cell phones, having had a head injury, or having been exposed to certain chemicals at work or to magnetic fields are important risk factors. Studies have not shown consistent links between these possible risk factors and brain tumors, but additional research is needed.
People with brain tumors have several treatment options. The options are surgery, radiation therapy, and chemotherapy. Many people get a combination of treatments. The choice of treatment depends mainly on the following:
Your doctor can describe your treatment choices, the expected results, and the possible side effects. Because cancer therapy often damages healthy cells and tissues, side effects are common. Before treatment starts, ask your health care team about possible side effects and how treatment may change your normal activities. You and your health care team can work together to develop a treatment plan that meets your medical and personal needs.
You may want to talk with your doctor about taking part in a clinical trial, a research study of new treatment methods.
Your doctor may refer you to a specialist, or you may ask for a referral. Specialists who treat brain tumors include neurologists, neurosurgeons, neuro-oncologists, medical oncologists, radiation oncologists, and neuroradiologists. Your health care team may also include an oncology nurse, a registered dietitian, a mental health counselor, a social worker, a physical therapist, an occupational therapist, a speech therapist, and a physical medicine specialist. Also, children may need tutors to help with schoolwork.