A central nervous system (CNS) tumor may occur in the brain or the spinal cord. The brain is the center of thought, memory, and emotion. It controls the five senses (smell, touch, taste, hearing, and sight), movement, and other basic functions of the body, including heartbeat, circulation, and breathing. The spinal cord consists of nerves that carry information back and forth between the body and the brain.
When a tumor is located in the CNS, it is especially problematic because a person's thought processes and movements can be affected. This tumor also may be challenging to treat because the tissues surrounding the tumor may be vital to the body's functioning.
Anatomy of the brain
The brain is composed of four major parts: the cerebrum, cerebellum, brain stem, and meninges.
The cerebrum, the largest part of the brain, contains two cerebral hemispheres and is divided into four lobes where specific functions occur.
The frontal lobe, which controls reasoning, emotions, problem solving, and parts of speech and movement
The parietal lobe, which controls the sensations of touch, pressure, pain, and temperature
The temporal lobe, which controls memory and the sense of hearing
The occipital lobe, which controls vision
The cerebellum, or "little brain," is located beneath the cerebrum. The cerebellum controls coordination and balance.
The brain stem, which is the lowest portion of the brain and connects to the spinal cord, controls involuntary functions essential for life, such as the beating of the heart and breathing.
The meninges are the membranes that surround and protect the brain and spinal cord. There are three meningeal layers, called the dura mater, arachnoid, and pia arachnoid.
Types of CNS tumors
Cancer begins when cells grow uncontrollably and form a mass called a tumor. There are many different types of CNS tumors. Some are malignant (cancerous), which means that they invade other tissues and spread to other areas of the body. Others are less aggressive, either low grade or benign (noncancerous), which means they are not invasive (aggressive). The following are the most common types of CNS tumors in children:
Approximately 3,200 central nervous system tumors are diagnosed each year in children under the age of 20. About 800 of these are considered benign (non-cancerous) tumors.
Central nervous system tumors are the second most common childhood cancer, after leukemia. The overall five-year relative survival rate (the percentage of patients who survive at least five years after the cancer is detected, excluding those who die from other diseases) for this cancer is 74%.
Cancer survival statistics should be interpreted with caution. These 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 CNS tumor. Because the survival statistics are measured in five-year (or sometimes one-year) intervals, they may not represent advances made in the treatment or diagnosis of this cancer.
Statistics adapted from the American Cancer Society's publication, Cancer Facts and Figures 2008.
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.
The cause of a CNS tumor in children is not known. Researchers are studying a variety of possible causes of CNS tumors, including viruses. Different types of CNS tumors occur in different age groups. Some types of CNS tumors are more common in children under age three, for example. Head injury does not appear to cause a CNS tumor.
A small number of CNS tumors occur in families. Only a small percentage of children with a brain tumor have identifiable genetic causes, usually in association with a familial disease called neurofibromatosis. Neurofibromatosis is an inherited disorder that causes neurofibromas (benign tumors) to form on peripheral nerves in the body, brown spots on the skin, and deformities of tissues and bones. Neurofibromatosis is also called Recklinghausen's disease or von Recklinghausen's disease. For more information, review Cancer.Net's Guide to Neurofibromatosis Type 1 and Neurofibromatosis Type 2. Other, less common genetic conditions associated with a higher risk of a CNS tumor include Li-Fraumeni syndrome, tuberous sclerosis, nevoid basal cell syndrome, and Turcot syndrome.
Children with a CNS tumor may experience the following symptoms. Sometimes, children with a CNS tumor do not show any of these symptoms. Or, these symptoms may be caused by a medical condition that is not a tumor. If you are concerned about a symptom on this list, please talk to your child's doctor.
The symptoms depend on where the tumor is located. A tumor in the brain can affect any of the brain's functions. The following symptoms may indicate the presence of a CNS tumor:
A seizure or convulsion
Staring or repetitive automatic movements (a neck tilt or a squint)
Unexplained, persistent nausea and projectile vomiting
Weakness or clumsiness that seems to get worse (difficulty walking and balancing)
Early or delayed puberty, or delayed or abnormal growth
Sleep apnea (periodically stop breathing while asleep)
Vision problems
Headache, which may wake a child up at night or develop early in the morning
Pain, especially back pain
Irritability, listlessness, or changes in personality
In a baby, the only symptom may be that the head is growing too fast. An infant's skull can expand to make room for a growing tumor, so the baby may have a larger than normal head.
Doctors use many tests to diagnose a tumor and determine if it has metastasized (spread). Some tests may also determine which treatments may be the most effective. For most types of tumors, a biopsy is the only way to make a definitive diagnosis of cancer. 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 doctor may consider these factors when choosing a diagnostic test:
Age and medical condition
The type of tumor
Severity of symptoms
Previous test results
In addition to a physical examination, the following tests may be used to diagnose a CNS tumor:
Computed tomography (CT or CAT) scan. A CT scan creates a three-dimensional picture of the inside of the child's 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 (a special dye) is injected into a patient's vein to provide better detail.
Magnetic resonance imaging (MRI). An MRI uses magnetic fields, not x-rays, to produce detailed images of the brain and spinal column. MRIs may create more detailed pictures than CT scans.
Biopsy. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. The sample removed from the biopsy is analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease). The type of biopsy performed will depend on the location of the tumor.
Staging is a way of describing a cancer, 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 cancer's stage, so staging may not be complete until all the tests are finished.
Several types of childhood CNS tumors can spread through the spinal fluid pathways that surround the brain and the spine. In most cases, a tumor is described as either high-grade or low-grade, depending on how much of the tumor is left after surgery, the child's age, and whether the tumor has metastasized. This information helps the doctor plan the treatment and determine the child's prognosis (chance of recovery). In general, low-grade tumors have a better prognosis.
Clinical trials are the standard of care for the treatment of children with cancer. In fact, 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. Cancer in children is rare, so it can be hard for doctors to plan treatments unless they know what has been most effective in other children. 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. 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 type of treatment used depends on the type of CNS tumor and the age of the child. Radiation therapy is often limited in children younger than three years old, because extensive radiation therapy can cause learning and memory problems later on in the child's life.
Type of CNS Tumor
Treatment Commonly Used
Astrocytoma
Low-grade astrocytomas: Surgery alone, or surgery plus radiation therapy, or radiation therapy alone for older children; surgery plus chemotherapy or limited radiation therapy for younger children High-grade astrocytomas: Surgery plus radiation therapy and chemotherapy
Brain stem glioma
Radiation therapy, with or without chemotherapy
Ependymoma
Surgery and radiation therapy; possibly chemotherapy
Germ cell tumor
Surgery and radiation therapy, with or without chemotherapy
Medulloblastoma
Surgery, radiation therapy, and chemotherapy
Surgery
Surgery is almost always used to determine what type of tumor it is, either through a biopsy or in the course of treating a CNS tumor when it is possible to remove the tumor without significant damage to the brain. The goal of most brain tumor therapies is complete surgical removal of the tumor. Sometimes, a tumor spreads and grows between normal nerve cells, making surgery difficult. In certain cases, surgery can damage parts of the brain near to the tumor, affecting arm and leg movement, breathing, swallowing, eye movement, or consciousness. Some tumors cannot be reached by surgery because of their location; these tumors are called inoperable.
Radiation therapy
Radiation therapy uses x-rays or other high-energy particles to kill cancer cells. The most common type of radiation treatment is called external-beam radiation therapy, which is radiation given from a machine outside the body. Fatigue, drowsiness, nausea, vomiting, and headache are common side effects of radiation therapy. 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.
Stereotactic radiosurgery is a way to deliver high doses of radiation therapy directly to a tumor and not to healthy tissues. This technique produces detailed, three-dimensional maps of the brain and tumor, so doctors can pinpoint where to deliver the radiation treatment. It works best for a tumor that is only in one area of the brain, and certain benign tumors.
Chemotherapy
Chemotherapy uses drugs to kill cancer cells. Systemic chemotherapy is delivered through the bloodstream, targeting cancer cells throughout the body.
Chemotherapy is effective for many malignant types of brain tumors. Depending upon the tumor type, chemotherapy may be given immediately after a biopsy or surgery or following radiation therapy. In some instances, chemotherapy is used at the same time as radiation therapy.
Chemotherapy may also be given directly into the spinal canal, in a procedure called intrathecal chemotherapy, to treat cancer cells along the surfaces of the brain and spine. This procedure is still being investigated.
Because chemotherapy attacks rapidly dividing cells, including those in normal tissues such as the hair, lining of the mouth, intestines, and bone marrow, children receiving chemotherapy may lose their hair, develop mouth sores, or have nausea and vomiting. In addition, chemotherapy may lower the body's resistance to infection, lead to increased bruising and bleeding, and cause fatigue. These side effects can be controlled during treatment and usually go away after chemotherapy is completed. The severity of the side effects depends on the type and amount of the drug being given, and the length of time the child receives the drug.
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 they've been prescribed, their purpose, and their potential side effects or interactions with other medications. Learn more about your child's prescriptions through Cancer.Net's Drug Information Resources, which provides links to searchable drug databases.
Recurrent CNS tumor
Treatment for a recurrent CNS tumor (a tumor that comes back after treatment) depends on three factors:
The type of tumor
Whether the tumor recurred in the place where it originally began or in another part of the brain or body
The type of treatment the child received for the original tumor
Depending on individual circumstances, the doctor may recommend surgery, radiation therapy, chemotherapy, or stem cell transplantation.
In a bone marrow/stem cell transplantation, the doctor first gives high doses of chemotherapy to destroy the tumor, which also destroys the child's bone marrow (where blood cells are made). High-dose chemotherapy is most effective when there is little tumor left after surgery. Stem cells previously harvested (collected) from the child's blood or a bone marrow sample previously removed from the child's own bone marrow is used to replace the destroyed bone marrow. This is called an autologous transplant (AUTO). Because the child receives his or her own stem cells or bone marrow, there is no risk of tissue rejection as may be seen in other types of bone marrow transplantations.
Doctors and scientists are always looking for better ways to treat patients with a childhood CNS tumor. A clinical trial is a way to test a new treatment in order to prove that it is safe, effective, and possibly better than a standard treatment. Patients 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.
Patients decide to participate in clinical trials for many reasons. For some patients, a clinical trial is the best treatment option available. Because standard treatments are not perfect, patients are often willing to face the added uncertainty of a clinical trial in the hope of a better result. Other patients volunteer for clinical trials because they know that finding new drugs and other therapies is the only way to make progress in treating a childhood CNS tumor. Even if they do not benefit directly from the clinical trial, their participation may benefit future patients with a childhood CNS tumor.
To join a clinical trial, patients must complete a learning 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.
The tumor and its treatment can cause a variety of side effects; some are easily controlled and others require specialized care. Below are some of the side effects that are more common to a CNS tumor and its treatments. For more detailed information on managing these and other side effects, visit the Cancer.Net Managing Side Effects section.
Anemia. Anemia is common in people with cancer, especially those receiving chemotherapy. Anemia is an abnormally low level of red blood cells (RBCs). RBCs contain hemoglobin (an iron protein) that carries oxygen to all parts of the body. If the level of RBCs is too low, parts of the body do not get enough oxygen and cannot work properly. Most people with anemia feel tired or weak. The fatigue (tiredness) associated with anemia can seriously affect quality of life and make it more difficult for patients to cope with cancer and treatment side effects.
Fatigue (tiredness). Fatigue is extreme exhaustion or tiredness, and is the most common problem that people with cancer experience. More than half of patients experience fatigue during chemotherapy or radiation therapy, and up to 70% of patients with advanced cancer experience fatigue. Patients who feel fatigue often say that even a small effort, such as walking across a room, can seem like too much. Fatigue can seriously impact family and other daily activities, can make patients avoid or skip cancer treatments, and may even impact the will to live.
Hair loss (alopecia). A potential side effect of radiation therapy and chemotherapy is hair loss. Radiation therapy and chemotherapy cause hair loss by damaging the hair follicles responsible for hair growth. Hair loss may occur throughout the body, including the head, face, arms, legs, underarms, and pubic area. The hair may fall out entirely, gradually, or in sections. In some cases, the hair will simply thin-sometimes unnoticeably-and may become duller and dryer. Losing one's hair can be a psychologically and emotionally challenging experience and can affect a patient's self-image and quality of life. However, the hair loss is usually temporary, and the hair often grows back.
Mouth sores (mucositis). Mucositis is an inflammation of the inside of the mouth and throat, leading to painful ulcers and mouth sores. It occurs in up to 40% of patients receiving chemotherapy treatments. Mucositis can be caused by a chemotherapy drug directly, the reduced immunity brought on by chemotherapy, or radiation treatment to the head and neck area.
Nausea and vomiting. Vomiting, also called emesis or throwing up, is the act of expelling the contents of the stomach through the mouth. It is a natural way for the body to rid itself of harmful substances. Nausea is the urge to vomit. Nausea and vomiting are common in patients receiving chemotherapy for cancer and in some patients receiving radiation therapy. Many patients with cancer say they fear nausea and vomiting more than any other side effects of treatment. When it is minor and treated quickly, nausea and vomiting can be quite uncomfortable but cause no serious problems. Persistent vomiting can cause dehydration, electrolyte imbalance, weight loss, depression, and avoidance of chemotherapy.
Nervous system disturbances. Nervous system disturbances can be caused by many different factors, including cancer, cancer treatments, medications, or other disorders. Symptoms that result from a disruption or damage to the nerves caused by cancer treatment (such as surgery, radiation treatment, or chemotherapy) can appear soon after treatment or many years later. See Managing Side Effects: Nervous System Disturbances for the most common symptoms.
After treatment for a CNS tumor 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 a childhood CNS tumor should have life-long, follow-up care.
Based on the type of treatment the 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. For example, craniospinal radiation therapy can cause cognitive and endocrine symptoms over time, although the severity can vary greatly depending on the dose administered and the age of the child. Similarly, the risks and potential side effects of surgery vary widely, depending on the location and growth characteristics of the tumor. Likewise, the risks of chemotherapy and the likelihood of second cancers also strongly depend on the drugs used and their doses. Your 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 Late Effects of Childhood Cancer.
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 CNS 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.
Research about childhood CNS tumors is ongoing. The following advances may still be under investigation in clinical trials and may not be approved or available at this current time. Always discuss all diagnostic and treatment options with your doctor.
New medications. Doctors are examining new forms of drug therapy that are designed to increase the chances for tumor control.
Improved diagnostic imaging techniques. 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 during treatment.
Functional MRI (fMRI) is an imaging technique that identifies the parts of the brain that control speech, hearing, vision, touch, and movement. The specific locations of these functions are slightly different in every individual, so fMRI allows surgeons to plan surgery around these areas.
Image-guided stereotaxis allows surgeons to visualize and operate on the brain using three-dimensional outlines of the brain and the tumor. Along with specialized software, these images help guide the surgeon to the tumor. Tumors that were once inoperable are now being removed with this technique.
MR spectroscopy (MRS) and positron emission tomography (PET) scans are also being used to examine tumor metabolic activity. Whether these techniques will improve a doctor's ability to predict how a tumor will behave is still under review.
Improved methods of delivering radiation treatment. Doctors are experimenting with new techniques for delivering radiation therapy to certain types of tumors. These methods produce detailed, three-dimensional maps of the brain and tumor, so doctors can minimize radiation therapy to healthy tissues and focus on the tumor. This can reduce a child's exposure to radiation and minimize the long-term effects in the child.
Use of biologic markers to characterize tumors. Doctors are looking at various proteins and DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) markers in blood samples and tumor tissues of children with cancer to help predict how aggressive a tumor will behave. This information may help doctors treat the tumor more effectively.
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:
What type of tumor has been diagnosed?
Are other tests needed to confirm this diagnosis?
What is your familiarity with my child's tumor type and its treatment?
What are the treatment options?
What clinical trials are open to my child?
What treatment plan do you recommend? Why?
What are the chances for success with the planned therapy?
What are the potential side effects of each treatment option, both in the short term and long term?
Who is part of the treatment team, and what does each team member do?
What support services are available for my child and my family?
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