The brain is one of the most important organs in the body. It is the source of our movements, our vital activities, our thoughts, and our sensations of the world around us.
When cells inside the brain begin to replicate at an abnormal rate, a tumor is formed. Tumors can be either benign or malignant. Benign tumors are usually not cancer, do not invade nearby tissue, and when removed do not recur. Malignant tumors are made up of cancer cells. They can press on areas of the brain and disrupt its function, and may invade and grow into the healthy tissue around them.
Doctors refer to some brain tumors by grade - from low grade (grade I) to high grade (grade IV). The grade of a tumor refers to the way the cells look under a microscope. Cells from higher grade tumors are more abnormal looking and generally grow faster than cells from lower grade tumors; higher grade tumors are more malignant than lower grade tumors.
Tumors that begin in brain tissue are known as primary brain tumors and are classified by the type of tissue in which they begin. The most common brain tumors are gliomas, which begin in the glial (supportive) tissue. There are several types of gliomas:
There are other types of brain tumors that do not begin in glial tissue. Some of the most common are described below:
Treatment for a brain tumor depends on a number of factors. Among these are the type, location, and size of the tumor, as well as the patient's age and general health. Brain tumors are treated with surgery, radiation therapy, and chemotherapy; depending on the patient's needs, several methods may be used.
Before treatment begins, most patients are given steroids, which are drugs that relieve swelling (edema). They may also be given anticonvulsant medicine to prevent or control seizures. If hydrocephalus is present, the patient may need a shunt to drain the cerebrospinal fluid. A shunt is a long, thin tube placed in a ventricle of the brain and then threaded under the skin to another part of the body, usually the abdomen. It works like a drainpipe: Excess fluid is carried away from the brain and is absorbed in the abdomen. (In some cases, the fluid is drained into the heart.)
Surgery is the usual treatment for most brain tumors. To remove a brain tumor, a neurosurgeon makes an opening in the skull. This operation is called a craniotomy. Whenever possible, the surgeon attempts to remove the entire tumor. However, if the tumor cannot be completely removed without damaging vital brain tissue, the doctor removes as much of the tumor as possible. Partial removal helps to relieve symptoms by reducing pressure on the brain and reduces the amount of tumor to be treated by radiation therapy or chemotherapy.
Some tumors cannot be removed. In such cases, the doctor may do only a biopsy. A small piece of the tumor is removed so that a pathologist can examine it under a microscope to determine the type of cells it contains. This helps the doctor decide which treatment to use.
Sometimes, a biopsy is done with a needle. Doctors use a special headframe (like a halo) and CT scans or MRI to pinpoint the exact location of the tumor. The surgeon makes a small hole in the skull and then guides a needle to the tumor. (Using this technique to do a biopsy or for treatment is called stereotaxis.)
Many patients and their families want to learn all they can about brain tumors and the treatment choices so they can take an active part in decisions about medical care. The doctor is the best person to answer these questions. When discussing treatment, the patient may want to talk with the doctor about research studies of new treatment methods. Such studies, called clinical trials, are designed to improve cancer treatment. More information about clinical trials is in the Clinical Trials section.
Researchers are finding better ways to treat brain tumors, and the chances of recovery keep improving. Still, it is natural for patients and their families to be concerned about the future. There are many resources available both on and off the web for patients and their families. Links to some good websites can be found on our web resources page, or check out our recommended reading list for patients and their families.