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.
A neuroblastoma is the most common malignant tumor in infancy and one of the most common tumors in children in general. About 90 percent of all neuroblastomas occur in children under 5 years of age. The cause of a neuroblastoma is unknown. Most of these tumours develop spontaneously. However, they rarely occur in a family group.
Neuroblastoma is a common childhood cancer that grows in parts of the nervous system or adrenal glands.
The symptoms of neuroblastoma 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. Children have a drooping eyelid, a small pupil, and decreased sweating on one side of the face.
About 90 to 95 percent of neuroblastomas produce hormones like adrenaline, 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.
- Computed tomography (CT) or magnetic resonance imaging (MRT)
- Sometimes bone marrow analysis and urine tests
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 may be taken to look for cancer cells.
A urine sample can be tested for excessive levels of adrenaline-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
- Bone scan
- 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 neuroblastoma has spread
The doctor uses all of this information to determine whether the tumor is low risk, intermediate risk, or high risk.
The prognosis depends on several factors, such as the age of the child at diagnosis, whether the tumour has spread, and certain characteristics of the tumour known as biological properties (e.g. appearance of the tumour under the microscope and some characteristics of the DNA within the tumour cells). Younger children whose tumour has not scattered have the best prognosis.
The survival rate of children with a disease that is attributed a low or average risk is about 90 percent. If the cancer was considered high-risk, the survival rate was about 15 percent. However, newer and more intensive treatment methods with combination therapies have improved the rate to over 50 percent.
- Surgical removal
- Sometimes radiation therapy or stem cell transplantation
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.
For diseases with medium or high risk or for inoperable tumours, radiotherapy can be used.
Immunotherapy is the latest way to treat children who have high-risk cancer. This therapy helps stimulate the body's immune system against cancer.