Brain Cancer Causes, Symptoms, Diagnosis And Treatment

Brain Cancer Causes, Symptoms, Diagnosis And Treatment


The Brain


Together, the brain and spinal cord form the central nervous system. This complex system is part of everything we do. It controls the things we choose to do -- like walk and talk -- and the things our body does automatically -- like breathe and digest food. The central nervous system is also involved with our senses -- seeing, hearing, touching, tasting, and smelling -- as well as our emotions, thoughts, and memory.

The brain is a soft, spongy mass of nerve cells and supportive tissue. It has three major parts: the cerebrum, the cerebellum, and the brain stem. The parts work together, but each has special functions.

The cerebrum, the largest part of the brain, fills most of the upper skull. It has two halves called the left and right cerebral hemispheres. The cerebrum uses information from our senses to tell us what is going on around us and tells our body how to respond. The right hemisphere controls the muscles on the left side of the body, and the left hemisphere controls the muscles on the right side of the body. This part of the brain also controls speech and emotions as well as reading, thinking, and learning.

The cerebellum, under the cerebrum at the back of the brain, controls balance and complex actions like walking and talking.

The brain stem connects the brain with the spinal cord. It controls hunger and thirst and some of the most basic body functions, such as body temperature, blood pressure, and breathing.

The brain is protected by the bones of the skull and by a covering of three thin membranes called meninges. The brain is also cushioned and protected by cerebrospinal fluid. This watery fluid is produced by special cells in the four hollow spaces in the brain, called ventricles. It flows through the ventricles and in spaces between the meninges. Cerebrospinal fluid also brings nutrients from the blood to the brain and removes waste products from the brain.

The spinal cord is made up of bundles of nerve fibers. It runs down from the brain through a canal in the center of the bones of the spine. These bones protect the spinal cord. Like the brain, the spinal cord is covered by the meninges and cushioned by cerebrospinal fluid.

Spinal nerves connect the brain with the nerves in most parts of the body. Other nerves go directly from the brain to the eyes, ears, and other parts of the head. This network of nerves carries messages back and forth between the brain and the rest of the body.

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About Brain Tumors


The body is made up of many types of cells. Each type of cell has special functions. Most cells in the body grow and then divide in an orderly way to form new cells as they are needed to keep the body healthy and working properly. When cells lose the ability to control their growth, they divide too often and without any order. The extra cells form a mass of tissue called a tumor. Tumors are benign or malignant.

  • Benign brain tumors do not contain cancer cells. Usually these tumors can be removed, and they are not likely to recur. Benign brain tumors have clear borders. Although they do not invade nearby tissue, they can press on sensitive areas of the brain and cause symptoms.
  • Malignant brain tumors contain cancer cells. They interfere with vital functions and are life threatening. Malignant brain tumors are likely to grow rapidly and crowd or invade the tissue around them. Like a plant, these tumors may put out "roots" that grow into healthy brain tissue. If a malignant tumor remains compact and does not have roots, it is said to be encapsulated. When an otherwise benign tumor is located in a vital area of the brain and interferes with vital functions, it may be considered malignant (even though it contains no cancer cells).

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.


Primary Brain Tumors


Tumors that begin in brain tissue are known as primary brain tumors. (Secondary tumors that develop when cancer spreads to the brain are discussed in the Secondary Brain Tumors section.) Primary brain tumors 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:

  • Astrocytomas arise from small, star-shaped cells called astrocytes. They may grow anywhere in the brain or spinal cord. In adults, astrocytomas most often arise in the cerebrum. In children, they occur in the brain stem, the cerebrum, and the cerebellum. A grade III astrocytoma is sometimes called anaplastic astrocytoma. A grade IV astrocytoma is usually called glioblastoma multiforme.
  • Brain stem gliomas occur in the lowest, stemlike part of the brain. The brain stem controls many vital functions. Tumors in this area generally cannot be removed. Most brain stem gliomas are high-grade astrocytomas.
  • Ependymomas usually develop in the lining of the ventricles. They may also occur in the spinal cord. Although these tumors can develop at any age, they are most common in childhood and adolescence.
  • Oligodendrogliomas arise in the cells that produce myelin, the fatty covering that protects nerves. These tumors usually arise in the cerebrum. They grow slowly and usually do not spread into surrounding brain tissue. Oligodendrogliomas are rare. They occur most often in middle-aged adults but have been found in people of all ages.

There are other types of brain tumors that do not begin in glial tissue. Some of the most common are described below:

  • Medulloblastomas were once thought to develop from glial cells. However, recent research suggests that these tumors develop from primitive (developing) nerve cells that normally do not remain in the body after birth. For this reason, medulloblastomas are sometimes called primitive neuroectodermal tumors (PNET). Most medulloblastomas arise in the cerebellum; however, they may occur in other areas as well. These tumors occur most often in children and are more common in boys than in girls.
  • Meningiomas grow from the meninges. They are usually benign. Because these tumors grow very slowly, the brain may be able to adjust to their presence; meningiomas often grow quite large before they cause symptoms. They occur most often in women between 30 and 50 years of age.
  • Schwannomas are benign tumors that begin in Schwann cells, which produce the myelin that protects the acoustic nerve -- the nerve of hearing. Acoustic neuromas are a type of schwannoma. They occur mainly in adults. These tumors affect women twice as often as men.
  • Craniopharyngiomas develop in the region of the pituitary gland near the hypothalamus. They are usually benign; however, they are sometimes considered malignant because they can press on or damage the hypothalamus and affect vital functions. These tumors occur most often in children and adolescents.
  • Germ cell tumors arise from primitive (developing) sex cells, or germ cells. The most frequent type of germ cell tumor in the brain is the germinoma.
  • Pineal region tumors occur in or around the pineal gland, a tiny organ near the center of the brain. The tumor can be slow growing pineocytoma) or fast growing (pineoblastoma). The pineal region is very difficult to reach, and these tumors often cannot be removed.

Secondary Brain Tumors


Metastasis is the spread of cancer. Cancer that begins in other parts of the body may spread to the brain and cause secondary tumors. These tumors are not the same as primary brain tumors. Cancer that spreads to the brain is the same disease and has the same name as the original (primary) cancer. For example, if lung cancer spreads to the brain, the disease is called metastatic lung cancer because the cells in the secondary tumor resemble abnormal lung cells, not abnormal brain cells.

Treatment for secondary brain tumors depends on where the cancer started and the extent of the spread as well as other factors, including the patient's age, general health, and response to previous treatment.

Possible Causes of Brain Cancer


The causes of brain tumors are not known. Researchers are trying to solve this problem. The more they can find out about the causes of brain tumors, the better the chances of finding ways to prevent them. Doctors cannot explain why one person gets a brain tumor and another doesn't, but they do know that no one can "catch" a brain tumor from another person. Brain tumors are not contagious.

Although brain tumors can occur at any age, studies show that they are most common in two age groups. The first group is children 3 to 12 years old; the second is adults 40 to 70 years old.

By studying large numbers of patients, researchers have found certain risk factors that increase a person's chance of developing a brain tumor. People with these risk factors have a higher-than-average risk of getting a brain tumor. For example, studies show that some types of brain tumors are more frequent among workers in certain industries, such as oil refining, rubber manufacturing, and drug manufacturing. Other studies have shown that chemists and embalmers have a higher incidence of brain tumors. Researchers also are looking at exposure to viruses as a possible cause. Because brain tumors sometimes occur in several members of the same family, researchers are studying families with a history of brain tumors to see whether heredity is a cause. At this time, scientists do not believe that head injuries cause brain tumors to develop.

In most cases, patients with a brain tumor have no clear risk factors. The disease is probably the result of several factors acting together.

Brain Cancer Symptoms


Brain cancer symptoms depend mainly on tumor size and their location in the brain. Symptoms of brain cancer are caused by damage to vital tissue and by pressure on the brain as the tumor grows within the limited space in the skull. They also may be caused by swelling and a buildup of fluid around the tumor, a condition called edema. Brain cancer symptoms may also be due to hydrocephalus, which occurs when the tumor blocks the flow of cerebrospinal fluid and causes it to build up in the ventricles. If a brain tumor grows very slowly, its symptoms may appear so gradually that they are overlooked for a long time.

The most frequent brain cancer symptoms include:

  • Headaches that tend to be worse in the morning and ease during the day,
  • Seizures (convulsions),
  • Nausea or vomiting,
  • Weakness or loss of feeling in the arms or legs,
  • Stumbling or lack of coordination in walking (ataxic gait),
  • Abnormal eye movements or changes in vision,
  • Drowsiness,
  • Changes in personality or memory, and
  • Changes in speech.

These symptoms may be caused by brain tumors or by other problems. Only a doctor can make a diagnosis.

Diagnosis for brain cancer


To find the cause of a person's symptoms, the doctor asks about the patient's personal and family medical history and performs a complete physical examination. In addition to checking general signs of health, the doctor does a neurologic exam. This includes checks for alertness, muscle strength, coordination, reflexes, and response to pain. The doctor also examines the eyes to look for swelling caused by a tumor pressing on the nerve that connects the eye and the brain.

Depending on the results of the physical and neurologic examinations, the doctor may request one or both of the following:

  • A CT (or CAT) scan is a series of detailed pictures of the brain. The pictures are created by a computer linked to an x-ray machine. In some cases, a special dye is injected into a vein before the scan. The dye helps to show differences in the tissues of the brain.
  • MRI (magnetic resonance imaging) gives pictures of the brain, using a powerful magnet linked to a computer. MRI is especially useful in diagnosing brain tumors because it can "see" through the bones of the skull to the tissue underneath. A special dye may be used to enhance the likelihood of detecting brain cancer.

The doctor may also request other tests such as:

  • A skull x-ray can show changes in the bones of the skull caused by a tumor. It can also show calcium deposits, which are present in some types of brain tumors.
  • A brain scan reveals areas of abnormal growth in the brain and records them on special film. A small amount of a radioactive material is injected into a vein. This dye is absorbed by the tumor, and the growth shows up on the film. (The radiation leaves the body within 6 hours and is not dangerous.)
  • An angiogram, or arteriogram, is a series of x-rays taken after a special dye is injected into an artery (usually in the area where the abdomen joins the top of the leg). The dye, which flows through the blood vessels of the brain, can be seen on the x-rays. These x-rays can show the tumor and blood vessels that lead to it.
  • A myelogram is an x-ray of the spine. A special dye is injected into the cerebrospinal fluid in the spine, and the patient is tilted to allow the dye to mix with the fluid. This test may be done when the doctor suspects a tumor in the spinal cord.

Treatment for brain cancer


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. The doctor develops a treatment plan 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, called clinical trials, are discussed in the Clinical Trials section.

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's likely to cost.

Here are some important questions to ask the doctor:

  • What type of treatment will I receive?
  • What are the expected benefits of treatment?
  • What are the risks and possible side effects of treatment?
  • What can be done about side effects?
  • Would a clinical trial be appropriate for me?
  • Will I need to change my normal activities? If so, for how long?
  • How often will I need to have checkups?

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 find that it also 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.

Treatment Methods


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 may also 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 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.)

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 material 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. Doctors use the techniques described in the Surgery section to pinpoint the exact location of the tumor. 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.

Side Effects of Treatment for brain cancer


Cancer treatment often causes side effects. These side effects occur because treatment to destroy cancer cells damages some healthy cells as well.

The side effects of cancer treatment vary. They depend on the type of treatment used and on the area being treated. Also, each person reacts differently. Doctors try to plan the patient's therapy to keep side effects to a minimum. They also watch patients very carefully so they can help with any problems that occur.

A craniotomy is a major operation. The surgery may damage normal brain tissue, and edema may occur. Weakness, coordination problems, personality changes, and difficulty in speaking and thinking may result. Patients may also have seizures. In fact, for a short time after surgery, symptoms may be worse than before. Most of the side effects of surgery lessen or disappear with time.

Most of the side effects of radiation therapy go away soon after treatment is over. However, some side effects may occur or persist long after treatment is complete.

Some patients have nausea for several hours after treatment. Patients receiving radiation therapy may become very tired as treatment continues. Resting is important, but doctors usually advise their patients to try to stay reasonably active. Radiation therapy to the scalp causes most patients to lose their hair. When it grows back, the new hair is sometimes softer and may be a slightly different color. In some cases, hair loss is permanent.

Skin reactions in the treated area are common. The scalp and ears may be red, itchy, or dark; these areas may look and feel sunburned. The treated area should be exposed to the air as much as possible but should be protected from the sun. Patients should not wear anything on the head that might cause irritation. Good skin care is important at this time. The doctor may suggest certain kinds of soap or ointment, and patients should not use any other lotions or creams on the scalp without the doctor's advice.

Sometimes brain cells killed by radiation form a mass in the brain. The mass may look like a tumor and may cause similar symptoms, such as headaches, memory loss, or seizures. Doctors may suggest surgery or steroids to relieve these problems. About 4 to 8 weeks after radiation therapy, patients may become quite sleepy or lose their appetite. These symptoms may last several weeks, but they usually go away on their own. Still, patients should notify the doctor if they occur.

Children who have had radiation therapy for a brain tumor may have learning problems or partial loss of eyesight. If the pituitary gland is damaged, children may not grow or develop normally.

The side effects of chemotherapy depend on the drugs that are given. In general, anticancer drugs affect rapidly growing cells, such as blood cells that fight infection, cells that line the digestive tract, and cells in hair follicles. As a result, patients may have a lower resistance to infection, loss of appetite, nausea, vomiting, or mouth sores. Patients may also have less energy and may lose their hair. These side effects usually go away gradually after treatment stops.

Some anticancer drugs can cause infertility. Women taking certain anticancer drugs may have symptoms of menopause (hot flashes and vaginal dryness; periods may be irregular or stop). Some drugs used to treat children and teenagers may affect their ability to have children later in life.

Certain drugs used in the treatment of brain tumors may cause kidney damage. Patients are given large amounts of fluid while taking these drugs. Patients may also have tingling in the fingers, ringing in the ears, or difficulty hearing. These problems may not clear up after treatment stops.

Treatment with steroids to reduce swelling in the brain may cause increased appetite and weight gain. Swelling of the face and feet is common. Steroids can also cause restlessness, mood swings, burning indigestion, and acne. However, patients should not stop using steroids or change their dose without consulting the doctor. The use of steroids must be stopped gradually to allow the body to adjust to the change.

Loss of appetite can be a problem for patients during therapy. People may not feel hungry when they are uncomfortable or tired. Some of the common side effects of cancer treatment, such as nausea and vomiting, can also make it hard to eat. Yet good nutrition is important because patients who eat well generally feel better and have more energy. Eating well means getting enough calories and protein to help prevent weight loss, regain strength, and rebuild normal tissues. Many patients find that eating several small meals and snacks during the day works better than trying to have three large meals.

Patients being treated for a brain tumor may develop a blood clot and inflammation in a vein, most often in the leg. This is called thrombophlebitis. A patient who notices swelling in the leg, leg pain, and/or redness in the leg should notify the doctor right away.

Doctors, nurses, and dietitians can explain the side effects of cancer treatment and can suggest ways to deal with them.

Rehabilitation and Followup Care

Rehabilitation


Rehabilitation is a very important part of the treatment plan. The goals of rehabilitation depend on the patient's needs and how the tumor has affected his or her daily activities. The medical team makes every effort to help patients return to their normal activities as soon as possible.

Patients and their families may need to work with an occupational therapist to overcome any difficulty in activities of daily living, such as eating, dressing, bathing, and using the toilet. If an arm or leg is weak or paralyzed, or if a patient has problems with balance, physical therapy may be necessary. Speech therapy may be helpful for individuals having trouble speaking or expressing their thoughts. Speech therapists also work with patients who are having difficulty swallowing.

If special arrangements are necessary for school-age children, they should be made as soon as possible. Sometimes, children have tutors in the hospital or after they go home from the hospital. Children who have problems learning or remembering what they learn may need tutors or special classes when they return to school.

Followup Care


Regular followup is very important after treatment for a brain tumor. The doctor will check closely to make sure that the tumor has not returned. Checkups usually include general physical and neurologic exams. From time to time, the patient will have CT scans or MRIs.

Patients who receive radiation therapy to large areas of the brain or certain anticancer drugs may have an increased risk of developing leukemia or a second tumor at a later time. Also, radiation that affects the eyes may lead to the development of cataracts. Patients should carefully follow their doctor's advice on health care and checkups. If any unusual health problem occurs, they should report it to the doctor as soon as it appears.

Support for Cancer Patients


Living with a serious disease is not easy. Everyone involved faces many problems and challenges. Finding the strength to cope with these difficulties is easier when people have helpful information and support services.

The doctor can explain the disease and give advice about treatment, going back to work or school, or other activities. If patients want to discuss concerns about the future, family relationships, and finances, it may also help to talk with a nurse, social worker, counselor, or clergy member.

Friends and relatives who have had personal experience with cancer can be very supportive. Also, it helps many patients to meet and talk with other people who are facing problems like theirs. Cancer patients often get together in self-help and support groups, where they can share what they have learned about cancer and its treatment and about coping with the disease. In addition to groups for adults with cancer, special support groups for children or teens with cancer or for parents whose children have cancer are available in many cities. It's important to keep in mind, however, that each patient is different. Treatments and ways of dealing with cancer that work for one person may not be right for another -- even if they both have the same kind of cancer. It's always a good idea to discuss the advice of friends and family members with the doctor.

Often, a social worker at the hospital or clinic can suggest local and national groups that will help with rehabilitation, emotional support, financial aid, transportation, or home care.

Living With a Brain Tumor


The diagnosis of a brain tumor can change the lives of patients and the people who care about them. These changes can be hard to handle. Patients and their families and friends may have many different and sometimes confusing emotions.

At times, patients and those close to them may feel frightened, angry, or depressed. These are normal reactions when people face a serious health problem. Most patients, including children and teenagers, find it helps to share their thoughts and feelings with loved ones. Sharing can help everyone feel more at ease and can open the way for others to show their concern and offer their support.

Worries about tests, treatments, hospital stays, rehabilitation, and medical bills are common. Parents may worry about whether their children will be able to take part in normal school or social activities. Doctors, nurses, social workers, and other members of the health care team may be able to calm fears and ease confusion. They can also provide information and suggest helpful resources.

Patients and their families are naturally concerned about what the future holds. Sometimes they use statistics to try to figure out whether the patient will be cured or how long he or she will live. It is important to remember, however, that statistics are averages based on large numbers of patients. They cannot be used to predict what will happen to a certain patient because no two cancer patients are alike. The doctor who takes care of the patient and knows that person's medical history is in the best position to discuss the patient's outlook (prognosis).

People should feel free to ask the doctor about their prognosis, but it is important to keep in mind that not even the doctor can tell exactly what will happen. When doctors talk about recovering from a brain tumor, they may use the term remission rather than cure. Even though many people recover completely, doctors use this term because a brain tumor can recur.

Clinical Trials


Researchers are looking for treatment methods that are more effective against brain tumors and have fewer side effects. When laboratory research shows that a new method has promise, doctors use it to treat cancer patients in clinical trials 3. These trials are designed to answer scientific questions and to find out whether the new approach is both safe and effective. Patients who take part in clinical trials make an important contribution to medical science and may have the first chance to benefit from improved treatment methods.

Many clinical trials of new treatments for brain tumors are under way. Doctors are studying new types and schedules of radiation therapy, new anticancer drugs, new drug combinations, and combinations of chemotherapy and radiation.

Scientists are trying to increase the effectiveness of radiation therapy by giving treatments twice a day instead of once. Also, they are studying drugs called radiosensitizers. These drugs make the cancer cells more sensitive to radiation. Another method under study is hyperthermia, in which the tumor is heated to increase the effect of radiation therapy.

Many drugs cannot reach brain cells because of the blood-brain barrier, a network of blood vessels and cells that filters blood going to the brain. Researchers continue to look for new drugs that will pass through the blood-brain barrier. Studies are under way using different techniques to temporarily disrupt the barrier so that drugs can reach the tumor.

In other studies, scientists are exploring new ways to give the drugs. Drugs may be injected into an artery leading to the brain or may be put directly into the ventricles. Doctors are also studying the effectiveness of placing tiny wafers containing anticancer drugs directly into the tumor. (The wafers dissolve over time.)

Researchers are also testing the use of very high doses of anticancer drugs. Because these higher doses may damage healthy bone marrow, doctors combine this treatment with bone marrow transplantation to replace the marrow that has been destroyed.

Biological therapy is a new way of treating brain tumors that is currently under study. This type of treatment is an attempt to improve the way the body's immune system fights disease.

Patients interested in taking part in a clinical trial should discuss this option with their doctor.

One way to learn about clinical trials is through PDQ, a computerized resource developed by the National Cancer Institute. This resource contains information about cancer treatment and about clinical trials in progress all over the country. The Cancer Information Service can provide PDQ information to patients and the public.