Neuroblastomas are unusual cancers of immature or developing nerve cells in infants or young children. They often metastasize (spread) to other parts of the body.
Neuroblastomas are malignant * tumors * of the autonomic nervous system * . They occur when primitive neurons (nerve cells) fail to mature normally and begin to divide uncontrollably. Neuroblastomas may release hormones * that cause changes in the body. They can also affect some brain functions.
About one-third of all neuroblastomas are diagnosed during the first year of life, and 79 percent are diagnosed by the age of four. Only about 2 percent of neuroblastomas occur in children over 10 years of age or in adults. These tumors are slightly more common in boys than in girls.
Two-thirds of neuroblastomas originate in the abdomen (commonly called the belly). About one-half of these begin in the nerve-like cells in the medulla at the center of the adrenal glands * , and one-half originate in clusters of nerves called ganglia in the abdomen. Other neuroblastomas may come from the chest or neck ganglia.
Sometimes, especially in very young infants, neuroblastoma cells die on their own and the tumor disappears. At other times, the neuroblastoma cells spontaneously mature into ganglion cells that do not continue to divide and the tumor becomes a benign ganglioneuroma, which means the tumor is not serious or cancerous. A ganglioneuroblastoma is a tumor that contains both malignant and nonmalignant cells.
The causes of neuroblastomas were not well understood as of 2016. Nerve and adrenal medulla cells develop from fetal * cells called neuroblasts. Neuroblastomas are believed to occur when neuroblasts fail to mature due to mutations in their DNA * . Instead, the neuroblasts continue to grow and divide.
About 1 to 2 percent of neuroblastomas appear to have a hereditary component, with other family members having had the cancer as infants. Children with this familial form tend to be diagnosed at a younger age, and they often develop neuroblastomas in two or more organs.
Neuroblastomas are the most common cancer in infants and the fourth most common cancer in children. There are about 700 new cases in the United States every year.
The symptoms of neuroblastomas depend on the original location of the tumor and how far the cancer has metastasized (spread). The most common sign is a lump or mass, usually in the abdomen. The abdomen may swell, and the child may complain of a stomachache. Masses can be found elsewhere in the body, such as the neck or back of the eye. Depending on the location of the neuroblastoma, symptoms may include constipation or breathing difficulty, vision changes, or behavioral problems. Neuroblastomas frequently spread to the bones, and older children may complain of bone pain or have difficulty walking.
Paraneoplastic (caused by cancer located elsewhere in the body) syndromes are associated with less common symptoms caused by hormonereleasing neuroblastomas:
Opsoclonus-myoclonus-ataxia syndrome, also known as “dancing eyes, dancing feet,” is an uncommon symptom characterized by irregular rapid eye movements, muscle spasms, difficulty walking, and possibly difficulty in speaking. Surprisingly, neuroblastomas that cause this syndrome are less life-threatening than other forms.
Because of their early age of onset, neuroblastomas can be difficult to diagnose. Up to 60 percent of cases are not diagnosed until they have already metastasized, especially to the lymph nodes * , bones, bone marrow * , liver, or skin. Rarely, neuroblastomas are diagnosed during a prenatal * ultrasound * . Sometimes neuroblastomas are discovered during tests for other childhood diseases. These cases usually have good outcomes and may not even require treatment.
About 90 percent of neuroblastomas overproduce chemicals called catecholamines * that can be detected in the blood or urine. Elevated levels of the chemical messengers dopamine * or norepinephrine * in the blood can be a sign of neuroblastoma. Additional tests measure blood cell counts, liver and kidney function, and salt balance.
Imaging tests used to diagnose and stage neuroblastomas include:
About one-half of neuroblastomas spread to the bone marrow. Bone marrow is sampled by aspiration * and biopsy to diagnose and stage the cancer.
Treatment for neuroblastoma usually includes one or more of the following:
Children who undergo bone marrow-destroying chemotherapy receive bone marrow transplants * with their own previously collected stem cells. This treatment has significantly increased the cure rate for neuroblastomas.
Early-stage neuroblastomas—before metastases * occur—have a cure rate of over 90 percent. Later-stage neuroblastomas have a cure rate of only 30 percent despite multimodal therapy (therapy that uses two or more forms of treatment, like surgery followed by radiation therapy or chemotherapy).
Children are placed in risk groups based on the cancer stage and other factors:
There was no identified way, as of 2016, to prevent the development of neuroblastomas. Several countries, including Japan, Germany, and Canada, attempted to implement newborn screening programs for neuroblastoma by measuring the levels of catecholamines in the urine, but these programs failed to improve the cure rate. However, a Canadian study found that eating foods fortified with folate (folic acid) during pregnancy cuts the risk of neuroblastoma by 60 percent. Folate fortification of grain products has been required in the United States since 1998.
See also Cancer: Overview • Tumor
Christiansen, H., N. M. Christiansen, and W. Kiess. Progressive Neuroblastoma: Innovation and Novel Therapeutic Strategies. Basel, Switzerland: S. Karger, 2015.
Moyes, Judy S. E., and V. Ralph McCready. Neuroblastoma: mIBG in Its Diagnosis and Management. New York: Springer, 2013.
American Cancer Society. “What Is Neuroblastoma?” http://www.cancer.org/cancer/neuroblastoma/detailedguide/neuroblastomawhat-is-neuroblastoma (accessed March 10, 2016).
PubMed Health. “Neuroblastoma.” U.S. National Library of Medicine. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0024889/ (accessed March 10, 2016).
American Cancer Society. 250 Williams St. NW, Atlanta, GA 30303. Toll-free: 800-227-2345. Website: http://www.cancer.org (accessed March 10, 2016).
Children's Neuroblastoma Cancer Foundation. 360 W. Schick Rd., Suite 23, #211, Bloomingdale, IL 60108. Toll-free: 866-671-2623. Website: www.cncfhope.org (accessed March 10, 2016).
National Cancer Institute. BG 9609 MSC 9760, 9609 Medical Center Dr., Bethesda, MD 20892-9760. Toll-free: 800-422-6237. Website: http://www.cancer.gov (accessed March 10, 2016).
* malignant (ma-LIG-nant) refers to a condition that is severe and progressively worsening.
* tumors (TOO-morz) are abnormal growths of body tissue that have no known cause or physiologic purpose. Tumors may or may not be cancerous.
* autonomic nervous system is a branch of the peripheral nervous system that controls various involuntary body activities, such as body temperature, metabolism, heart rate, blood pressure, breathing, and digestion. The autonomic nervous system has two parts—the sympathetic and parasympathetic branches.
* hormones are chemical substances that are produced by various glands and sent into the bloodstream carrying messages that have certain specific on other parts of the body.
* adrenal glands (a-DREEN-al glands) are the pair of endocrine organs located near the kidneys.
* fetal (FEE-tal) refers to an unborn human after it is an embryo, from nine weeks after fertilization until childbirth.
* DNA or deoxyribonucleic acid (dee-OX-see-ry-bo-nyoo-klay-ik AH-sid) is the specialized chemical substance that contains the genetic code necessary to build and maintain the structures and functions of living organisms.
* lymph nodes (LIMF) are small bean-shaped masses of tissue containing immune system cells that fight harmful microorganisms. Lymph nodes may swell during infections. bone marrow is the soft tissue inside bones where blood cells are made.
* norepinephrine (NOR-e-pi-nefrin) is a body chemical that can increase the arousal response, heart rate, and blood pressure.
* prenatal (pre-NAY-tal) means existing or occurring before birth, with reference to the fetus.
* ultrasound, also called a sonogram, is a diagnostic test in which sound waves passing through the body create images on a computer screen.
* catecholamines (kat-e-KO-lameens) are hormones and neurotransmitters like epinephrine, norepinephrine, and dopamine.
* dopamine (DOE-puh-meen) is a neurotransmitter in the brain that is involved in the brain structures that control motor activity (movement).
* biopsy (BI-op-see) is a test in which a small sample of skin or other body tissue is removed and examined for signs of disease.
* antibodies (AN-tih-bah-deez) are protein molecules produced by the body's immune system to help fight specific infections caused by microorganisms, such as bacteria and viruses.
* aspiration (as-puh-RAY-shun) is the sucking of fluid or other material out of the body, such as the removal of a sample of joint fluid through a needle inserted into the joint.
* radiation therapy is a treatment that uses high-energy radiation from x-rays and other sources to kill cancer cells and shrink cancerous growths.
* transplants (TRANS-plantz) are organs or tissues from another body used to replace a poorly functioning organ or tissue.
* receptors are cell structures that form a chemical bond with specific substances, such as neurotransmitters.
* chromosome (KRO-mo-zom) is a unit or strand of DNA, the chemical substance that contains the genetic code to build and maintain a living being. Humans have 23 pairs of chromosomes, for a total of 46.
* metastases (me-TAS-ta-seez) are new tumors formed when cancer cells from a tumor spread to other parts of the body.
* genes (JEENS) are chemical structures composed of deoxyribonucleic acid (DNA) that help determine a person's body structure and physical characteristics. Inherited from a person's parents, genes are contained in the chromosomes found in the body's cells.