Brain Stem GliomaLast Updated: July 31, 2009 This section has been reviewed and approved by the Cancer.Net Editorial Board, 06/09 Overview
Brain stem glioma begins when normal cells in the brain stem begin to change and grow uncontrollably, forming a mass called a tumor. A tumor can be benign (noncancerous) or malignant (cancerous, meaning it can spread to other parts of the body). A glioma is a tumor that grows from a glial cell, which is a supportive cell in the brain. The brain stem connects the brain to the spinal cord. It is the lowest portion of the brain, located above the back of the neck. The brain stem controls many of the body’s basic functions, such as motor skills, sensory activity, coordination and walking, the beating of the heart, and breathing. It has three parts:
Brain stem glioma is most often diffused (spread freely) through the brain stem by the time of diagnosis. This type of tumor is typically very aggressive, meaning that it grows and spreads quickly. A small percentage of brain stem tumors are very localized or focal tumors. A focal tumor is often a low-grade (the tumor cells look similar to normal cells) tumor that is less aggressive. Brain stem glioma occurs most commonly in children between five and 10 years old. Most brain stem tumors develop in the pons and grow in a part of the brain stem where it can be difficult to perform surgery, making brain stem glioma challenging to treat. Statistics Approximately 3,400 central nervous system (CNS; brain and spinal cord) tumors are diagnosed each year in children under the age of 20. About 850 of these are considered benign tumors. Central nervous system tumors are the second most common childhood cancer after leukemia and brain tumors. Cancer statistics should be interpreted with caution. Estimates are based on data from thousands of cases of this type of cancer, but the actual risk for a particular individual may differ. It is not possible to tell a person how long he or she will live with a brain stem glioma. Statistics adapted from the American Cancer Society's publication, Cancer Facts and Figures 2009 and the Central Brain Tumor Registry of the United States. Find out more about basic cancer terms used in this section. Medical Illustrations
Risk Factors
A risk factor is anything that increases a person’s chance of developing cancer. Some risk factors can be controlled, such as smoking, and some cannot be controlled, such as age and family history. Although risk factors can influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. Doctors and researchers don’t know what causes most childhood cancers. Some evidence indicates that genetic factors may play a role in a small percentage of brain stem gliomas. Genetic conditions associated with a higher risk of developing a CNS tumor include Li-Fraumeni syndrome, tuberous sclerosis, nevoid basal cell carcinoma syndrome, and Turcot syndrome. Symptoms
Children with a brain stem glioma may experience the following symptoms. Sometimes, children with brain stem glioma do not show any of these symptoms. Or, these symptoms may be caused by a medical condition that is not a brain stem glioma. If you are concerned about a symptom on this list, please talk with your child’s doctor.
Diagnosis
Doctors use many tests to diagnose a brain stem glioma and determine if it has metastasized (spread). Some tests may also determine which treatments may be the most effective. For most tumors, a biopsy is the only way to make a definitive diagnosis. However, biopsies are rarely used and are often specifically avoided in children with diffuse brain stem glioma because the results of the biopsy do not influence treatment, and they can have major risks. In addition, the diagnosis can often be made by magnetic resonance imaging (MRI) alone (see below). Diffuse brain stem glioma is unlike most other tumors in this regard. For a focal tumor, a biopsy and surgical tumor removal may be considered. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may be used to find out whether the cancer has metastasized. Your child’s doctor may consider these factors when choosing a diagnostic test:
In addition to a physical examination, the following tests may be used to diagnose a brain stem glioma: MRI. An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium (a special dye) may be injected into a patient’s vein to create a clearer picture. Computed tomography (CT or CAT) scan. A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium is injected into a vein to provide better detail. For a brain stem glioma, this test generally does not provide enough information to make a definite diagnosis, and an MRI is required. Biopsy.A biopsy is the removal of a small amount of tissue for examination under a microscope. A biopsy is generally not done for the more common, diffuse type of brain stem tumor. However, for a focal tumor, it is often used to determine the type of tumor. If possible, a neurosurgeon (a specialist who operates on the brain and spine) will remove a small piece of tissue from the brain. The sample removed during the biopsy is analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease). Learn more about what to expect when having common tests, procedures, and scans. Find out more about common terms used during a diagnosis of cancer. Staging
Staging is a way of describing a tumor, such as where it is located, if or where it has spread, and if it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the tumor's stage, so staging may not be complete until all of the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis (chance of recovery). There are different stage descriptions for different types of tumors. There is no formal staging system for childhood brain stem glioma. A tumor may be classified as either diffuse or focal. In addition, the tumor may be classified by its grade, which is a measure of how much the tumor cells appear like normal cells. Low-grade tumors are less aggressive than high-grade tumors. Diffuse brain stem glioma. This type of tumor spreads freely throughout the pons and often spreads to the midbrain, the medulla, or nearby parts of the brain. These tend to be high-grade tumors; they are very aggressive and contain abnormal-looking cells. Focal brain stem glioma. About 20% of brain stem tumors are focal, meaning they occur at one point or are contained within a small segment of the brain stem. They usually occur in the midbrain or medulla, rather than the pons. These are usually benign or low-grade tumors; they are less aggressive and the tumor cells look fairly normal. Recurrent brain stem glioma: Recurrent brain stem glioma is a tumor that comes back after treatment. Treatment
In general, cancer in children is uncommon, so it can be hard for doctors to plan treatments unless they know what has been most effective in other children. That’s why more than 60% of children with cancer are treated as part of a clinical trial. Clinical trials are research studies that compare standard treatments (the best treatments available) with newer treatments that may be more effective. Investigating new treatments involves careful monitoring using scientific methods, and all participants are followed closely to track progress. To take advantage of these newer treatments, all children with cancer should be treated at a specialized cancer center. Doctors at these centers have extensive experience in treating children with cancer and have access to the latest research. A doctor who specializes in treating children with cancer is called a pediatric oncologist. Many times, a team of doctors treats a child with cancer. Pediatric cancer centers often have extra support services for children and their families, such as nutritionists, social workers, and counselors. Special activities for kids with cancer may also be available. The treatment of brain stem glioma depends on the size and location of the tumor, whether the cancer has spread, and the child’s overall health. Three types of treatments are used to treat brain stem glioma in children: radiation therapy, chemotherapy, and surgery. Sometimes, the treatments are used in combination. Descriptions of these treatment options are listed below. Radiation therapy Radiation therapy is the most common treatment for brain stem glioma. Radiation therapy is the use of high-energy x-rays or other particles to kill tumor cells. A doctor who specializes in giving radiation therapy to treat a tumor is called a radiation oncologist. The most common type of radiation treatment is called external-beam radiation therapy, which is radiation given from a machine outside the body. When radiation therapy is given using implants, it is called internal radiation therapy or brachytherapy. Side effects from radiation therapy may include fatigue, mild skin reactions, upset stomach, and loose bowel movements. Most side effects go away soon after treatment is finished. Because radiation therapy can sometimes interfere with the normal growth and development of the child’s brain, the doctor may choose to treat the cancer in another way. To avoid or reduce the need for radiation treatment in young children, the doctor may first use chemotherapy to shrink the tumor. Learn more about radiation therapy. Chemotherapy Chemotherapy is the use of drugs to kill cancer cells. Systemic chemotherapy is delivered through the bloodstream, targeting cancer cells throughout the body. Chemotherapy is given by a medical oncologist, a doctor who specializes in treating cancer with medication. Some people may receive chemotherapy in their doctor’s office; others may go to the hospital. A chemotherapy regimen (schedule) usually consists of a specific number of cycles given over a specific time. Chemotherapy alone is not an effective treatment for brain stem glioma; however, sometimes, a doctor may use chemotherapy at the same time as or after radiation therapy. The side effects of chemotherapy depend on the individual and the dose used, but can include fatigue, risk of infection, nausea and vomiting, loss of appetite, and diarrhea. These side effects usually go away once treatment is finished. Learn more about chemotherapy and preparing for treatment. The medications used to treat cancer are continually being evaluated. Talking with your child’s doctor is often the best way to learn about the medications prescribed for your child, their purpose, and their potential side effects or interactions with other medications. Learn more about your child’s prescriptions by using searchable drug databases. Surgery Surgery is used to treat brain stem glioma only when the tumor’s appearance on an MRI scan is focal, which means that it may be possible to remove the cancer without damaging the brain, such as when a tumor grows out from the brain stem. For most children with diffuse types of brain stem glioma, surgery is not recommended or possible because of the location of the tumor and the risk involved. Learn more about cancer surgery. Recurrent brain stem glioma Treatment for recurrent brain stem glioma depends on two factors:
Depending on individual circumstances, the doctor may recommend either surgery or chemotherapy. Find out more about common terms used during cancer treatment. Clinical Trials Resources
Doctors and scientists are always looking for better ways to treat children with brain stem glioma. A clinical trial is a way to test a new treatment to prove that it is safe, effective, and possibly better than a standard treatment. The clinical trial may be evaluating a new drug, a new combination of existing treatments, a new approach to radiation therapy or surgery, or a new method of treatment or prevention. Children who participate in clinical trials are among the first to receive new treatments before they are widely available. However, there is no guarantee that the new treatment will be safe, effective, or better than a standard treatment. People decide to participate in clinical trials for many reasons. For some children, a clinical trial is the best treatment option available. Because standard treatments are not perfect, people are often willing to face the added uncertainty of a clinical trial in the hope of a better result. Other people volunteer for clinical trials because they know that finding new drugs and other therapies is the only way to make progress in treating brain stem glioma. Even if they do not benefit directly from the clinical trial, their participation may benefit future children with brain stem glioma. Sometimes people have concerns that, by participating in a clinical trial, they may receive no treatment by being given a placebo or a “sugar pill”. The use of placebos in cancer clinical trials is rare. When a placebo is used in a study, it is done with the full knowledge of the participants. Find out more about placebos in cancer clinical trials. To join a clinical trial, parents and children must participate in a process known as informed consent. During informed consent, the doctor should list all of the patient’s options, so the person understands how the new treatment differs from the standard treatment. The doctor must also list all of the risks of the new treatment, which may or may not be different from the risks of standard treatment. Finally, the doctor must explain what will be required of each patient in order to participate in the clinical trial, including the number of doctor visits, tests, and the schedule of treatment. Learn more about clinical trials, including patient safety, phases of a clinical trial, deciding to participate in a clinical trial, questions to ask the research team, and links to find cancer clinical trials. For specific topics being studied for brain stem glioma, learn more in the Current Research section. Side Effects
A tumor and its treatment can cause a variety of side effects. However, doctors have made major strides in recent years in reducing pain, nausea and vomiting, and other physical side effects of tumor treatments. Many treatments used today are less intensive but as effective as treatments used in the past. Doctors also have many ways to provide relief to patients when such side effects do occur. Fear of treatment side effects is common after a diagnosis of brain stem glioma, but it may be helpful to know that preventing and controlling side effects is a major focus of your child’s health-care team. Before treatment begins, talk with your child’s doctor about possible side effects of the specific treatments your child will be receiving. The specific side effects that can occur depend on a variety of factors, including the type of cancer, its location, the individual treatment plan (including the length and dosage of treatment), and the child’s overall health. Ask your child’s doctor which side effects are most likely to happen (and which are not), when side effects are likely to occur, and how they will be addressed by the health-care team if they do happen. Also, be sure to communicate with the doctor about side effects your child experiences during and after treatment. Learn more about the most common side effects of a tumor and different treatments, along with ways to prevent or control them. In addition to physical side effects, there may be psychosocial (emotional and social) effects as well. Learn more about the importance of addressing such needs, including concerns about managing the cost of medical care. Learn more about late effects or long-term side effects by reading the After Treatment section or talking with your child’s doctor. After Treatment
After treatment for brain stem glioma ends, talk with your child’s doctor about developing a follow-up care plan. This plan may include regular physical examinations and/or medical tests to monitor your child’s recovery for the coming months and years. All children treated for brain stem glioma should have life-long, follow-up care. The child’s follow-up care plan and the long-term risks following treatment depend on several factors, such as the type of tumor and its location, the age of the child at diagnosis, and the type of treatment. For example, craniospinal radiation therapy can cause cognitive (thought-process) and endocrine (hormonal) symptoms over time, although the severity can vary greatly depending on the dose given and the age of the child. Similarly, the risks and potential side effects of surgery vary widely, depending on the location and characteristics of the tumor.Likewise, the risks of chemotherapy and the likelihood of secondary cancers strongly depend on the specific drugs used and the dosage. For each of these issues, it is important to discuss the specific aspects of the tumor and the options for treatment with the neurosurgeon and neuro-oncologist (a medical doctor who specializes in cancer of the central nervous system) that are involved in the child's care. Based on the type of treatment your child received, the doctor will determine what examinations and tests are needed to check for long-term side effects and the possibility of secondary cancers. Your child’s doctor can recommend the necessary screening tests. Follow-up care should also address the child’s quality of life, including any developmental or emotional concerns. Learn more about childhood cancer survivorship. The child’s family is encouraged to organize and keep a record of the child’s medical information, so that as the child enters adulthood, he or she has a clear, written history of the diagnosis and details of the treatment given. The doctor’s office can help you compile this, and it should include recommendations from the doctor about the schedule for follow-up care. This information will be valuable to doctors who care for your child during his or her lifetime. Children who have had a tumor can also enhance the quality of their future by following established guidelines for good health into and through adulthood, including not smoking, maintaining a healthy weight, eating a balanced diet, and participating in regular physical activity. Talk with the doctor about developing a plan that is best for your child’s needs. Find out more about common terms used after cancer treatment is complete. Current Research
Research for brain stem glioma is ongoing. The following advances may still be under investigation in clinical trials and may not be approved or available at this time. Always discuss all diagnostic and treatment options with your child’s doctor. Improved methods of imaging and surgery. Imaging techniques are being developed that help surgeons pinpoint the tumor’s location to reduce or prevent tissue damage to the healthy parts of the brain. For example, image-guided stereotaxis allows surgeons to visualize and operate on the brain using three-dimensional computerized outlines of the brain and the tumor. Along with specialized software, these images help guide the surgeon to the tumor. Tumors that were once considered inoperable are now being removed using this technique. Improved methods of delivering radiation treatment. Conformal radiation therapy is a way to deliver high doses of radiation directly to a tumor and not healthy tissue. This technique produces detailed, three-dimensional maps of the brain and tumor, so doctors know exactly where to deliver the radiation therapy. In addition, advances under investigation in clinical trials include drugs designed to enhance the effect of radiation therapy or to slow or stop tumor growth. Questions to Ask the Doctor
Regular communication with your child’s doctor is important in making informed decisions about his or her health care. Consider asking the following questions of your child’s doctor:
Patient Information Resources
In addition to Cancer.Net, there are other sources of information about this type of cancer available online. Cancer.Net maintains a list of national, not-for-profit organizations that may be helpful in finding additional information, services, and support. As always, be sure to talk with your doctor about questions you may have about information you find about this disease. View organizations that offer information on this specific type of cancer. |
