Causes and treatments
Doctors generally divide brain tumors into the following categories to explain where or how they originate:
Primary. Primary brain tumors originate in the brain or close to it, such as in the skull, brain membranes (meninges), cranial nerves, pituitary gland or pineal gland. Most brain tumors in children are primary. Slightly more than one-fourth of all brain tumors are primary. The remaining are secondary (metastatic). It's not known what causes primary brain tumors. It's possible that heredity, environmental factors, viruses or other factors play a role in their development.
Some common types of primary tumors — named after the type of brain cells from which they originate — include acoustic neuromas (schwannomas), astrocytomas, medulloblastomas, meningiomas and oligodendrogliomas.
Secondary (metastatic) brain tumors are tumors that result from cancer that starts elsewhere in your body and then spreads (metastasizes) to your brain. Cancers of the lung and breast are most likely to spread to your brain. Sometimes, a brain tumor is the first sign of cancer that began elsewhere in your body.
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. Treatment methods and schedules often vary for children and adults. A treatment plan is developed to fit each patient's needs.
The patient's doctor may want to discuss the case with other doctors who treat brain tumors. Also, the patient may want to talk with the doctor about taking part in a research study of new treatment methods. Such studies are called clinical trials.
Many patients want to learn all they can about their disease and their treatment choices so they can take an active part in decisions about their medical care. A person with a brain tumor will have many questions, and the doctor is the best person to answer them. Most patients want to know what kind of tumor they have, how it can be treated, how effective the treatment is likely to be, and how much it is likely to cost.
Many people find it helpful to make a list of their questions before they see the doctor. Taking notes can make it easier to remember what the doctor says. Some patients also find that it helps to have a family member or friend with them when they talk with the doctor,either to take part in the discussion or just to listen.
Patients and their families have a lot to learn about brain tumors and their treatment. They should not feel that they need to understand everything the first time they hear it. They will have other chances to ask the doctor to explain things that are not clear.
Brain tumors are treated with surgery, radiation therapy, and chemotherapy. Depending on the patient's needs, several methods may be used. The patient may be referred to doctors who specialize in different kinds of treatment and work together as a team. This medical team often includes a neurosurgeon, a medical oncologist, a radiation oncologist, a nurse, a dietitian, and a social worker. The patient also might work with a physical therapist, an occupational therapist, and a speech therapist.
Before treatment begins, most patients are given steroids, which are drugs that relieve swelling (edema). They also may be given anticonvulsant medicine to prevent or control seizures. If hydrocephalus (a condition which results in fluid accumulation around the brain) 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 head frame (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).
Radiation therapy (also called radiotherapy) is the use of high-powered rays to damage cancer cells and stop them from growing. It is often used to destroy tumor tissue that cannot be removed with surgery or to kill cancer cells that may remain after surgery. Radiation therapy is also used when surgery is not possible.
Radiation therapy may be given in two ways. External radiation comes from a large machine. Generally, external radiation treatments are given 5 days a week for several weeks. The treatment schedule depends on the type and size of the tumor and the age of the patient. Giving the total dose of radiation over an extended period helps to protect healthy tissue in the area of the tumor.
Radiation can also come from radioactive materials placed directly in the tumor (implant radiation therapy). Depending on the material used, the implant may be left in the brain for a short time or permanently. Implants lose a little radioactivity each day. The patient stays in the hospital for several days while the radiation is most active.
External radiation may be directed just to the tumor and the tissue close to it or, less often, to the entire brain. (Sometimes the radiation is also directed to the spinal cord). When the whole brain is treated, the patient often receives an extra dose of radiation to the area of the tumor. This boost can come from external radiation or from an implant.
Stereotactic radiosurgery is another way to treat brain tumors. Treatment is given in just one session; high- energy rays are aimed at the tumor from many angles. In this way, a high dose of radiation reaches the tumor without damaging other brain tissue. (This use of radiation therapy is sometimes called the gamma knife).
Chemotherapy is the use of drugs to kill cancer cells. The doctor may use just one drug or a combination, usually giving the drugs by mouth or by injection into a blood vessel or muscle. Intrathecal chemotherapy involves injecting the drugs into the cerebrospinal fluid.
Chemotherapy is usually given in cycles: a treatment period followed by a recovery period, then another treatment period, and so on. Patients often do not need to stay in the hospital for treatment. Most drugs can be given in the doctor's office or the outpatient clinic of a hospital. However, depending on the drugs used, the way they are given, and the patient's general health, a short hospital stay may be necessary.