(See also Overview of Childhood Cancer.)
Neuroblastoma is a common childhood cancer that grows in parts of the nervous system or adrenal glands.
What causes neuroblastoma is not known.
Symptoms depend on where neuroblastomas develop, such as the abdomen, chest, bone, skin, or spinal cord.
Diagnosis usually involves an imaging test and a biopsy.
Treatment involves surgery for tumors that have not spread, chemotherapy, and sometimes radiation therapy.
A neuroblastoma develops in a certain kind of nerve tissue located in many places of the body. It usually originates in nerves in the abdomen or chest, most commonly in the adrenal glands (located above each kidney). Very rarely, a neuroblastoma originates in the brain. In over half of the children, the cancer has spread to other parts of the body by the time a doctor is consulted.
Neuroblastoma is the most common cancer among infants and one of the most common tumors among children of any age. About 90% of all neuroblastomas occur in children younger than 5 years. The cause is not known. Most of these tumors occur spontaneously. Rarely, neuroblastomas run in families.
The symptoms depend on where the neuroblastoma originated and whether and where it has spread, as in the following:
Originating in the abdomen: The first symptoms include a large abdomen, a sensation of fullness, and abdominal pain.
Originating in the chest or neck: The child may cough or have difficulty breathing.
Spread to the bones: The child has bone pain. If the cancer reaches the bone marrow, the number of various types of blood cells may be reduced. A reduced number of red blood cells (anemia) causes a weak and tired feeling and sometimes pale skin (pallor). A reduced number of platelets causes easy bruising and tiny purple spots on the skin. A reduced number of white blood cells lowers the resistance to infection.
Spread to the skin: Lumps appear.
Spread to the spinal cord: The arms and legs may feel weak, or children may not be able to voluntarily control some body parts.
Less commonly, children have symptoms of a disorder called Horner syndrome. In Horner syndrome, a tumor in the neck presses on nerves that affect one side of the face. People have a drooping eyelid, a small pupil, and decreased sweating on one side of the face.
About 90 to 95% of neuroblastomas produce hormones, such as epinephrine, which sometimes increase the heart rate and cause anxiety. Other syndromes associated with cancer (called paraneoplastic syndromes), such as uncontrollable eye movements (opsoclonus) and quick contractions of the arms and legs (myoclonus), can occur.
Early diagnosis of a neuroblastoma is not easy. Occasionally, routine prenatal ultrasonography detects neuroblastoma in a fetus. If the cancer has grown large enough, a doctor may be able to feel a lump in a child's abdomen.
A doctor who suspects a neuroblastoma does CT or MRI of the abdomen. If a tumor is found, a sample is taken and sent to a laboratory for examination (biopsy). A bone marrow sample is taken to look for cancer cells. A urine sample can be tested for excessive production of epinephrine-like hormones.
To see whether the cancer has spread, the doctor may do the following:
CT or MRI of the abdomen, pelvis, and chest and sometimes the brain
X-rays of bones
Examination of tissue samples from the liver, lungs, skin, bone marrow, or bone
A scan that uses a radioactive material known as metaiodobenzylguanidine (MIBG) that helps doctors see whether the cancer has spread
The doctor uses all of this information to determine whether the tumor is low risk, intermediate risk, or high risk.
Prognosis depends on several factors such as the child's age at diagnosis, whether the tumor has spread, and certain characteristics of the tumor called biologic features (for example, how the tumor looks under a microscope and some features of the DNA within the tumor cells). Younger children whose cancer has not spread have the best prognosis.
The survival rates for children who have low-risk and intermediate-risk disease are about 90%. The survival rate for children who have high-risk disease had been about 15% but this rate has improved to greater than 50% with newer and intensified methods of combined therapy, which are described in Treatment of Neuroblastoma.
Treatment of neuroblastoma is based on the risk category.
Cancer that has not spread can often be removed and cured by surgery.
Children who have intermediate-risk disease are given chemotherapy drugs such as vincristine, cyclophosphamide, doxorubicin, etoposide, and cisplatin. High-dose chemotherapy with stem cell transplantation is frequently used for children with high-risk disease. To reduce the risk of the cancer coming back after high-dose chemotherapy and stem cell transplantation, these children are given a drug called a retinoid, which is a chemical related to vitamin A, and immunotherapy.
Radiation therapy may be used for children with intermediate-risk or high-risk disease or when tumors are inoperable.
Immunotherapy is the latest way to treat children who have high-risk cancer. This therapy helps stimulate the body's immune system against cancer.