Neuroblastoma is the most common childhood cancer to develop outside the brain. It accounts for about 8% of childhood cancers. The average age at diagnosis is 2 years old. However, there is a specific subclass of neuroblastoma called Stage 4S, that occurs in infants younger than 1 year. Despite the presence of metastatic (disseminated) disease, these patients tend to do extremely well, and there have been instances of spontaneous regression of these neuroblastomas in these infants.

Neuroblastomas form in the nerve cells responsible for the body's "fight-or-flight" response, which is the ability to react to a life-threatening emergency. These nerve cells form the sympathetic nervous system.

Neuroblastomas usually form in one of two parts of the sympathetic nervous system:

• The adrenal glands. These glands in the abdomen produce the hormone adrenaline, also known as epinephrine, which is released in an emergency to help the body react. When a neuroblastoma develops in the adrenal gland, it typically grows into a large, firm abdominal mass that can compress nearby organs.



• The chain of sympathetic ganglia. These are collections of nerves near the backbone (spine). When a neuroblastoma develops along the sympathetic chain, it can invade nearby areas of the spine and cause injury to spinal nerves.

Neuroblastomas can develop in other areas of the body, including the chest, neck and pelvis, but this is less common.

As a neuroblastoma grows, it has the potential to spread (metastasize) to other areas, most commonly to the bone marrow, bones, liver and skin.

There is no conclusive evidence that neuroblastoma is related to any toxic chemical or environmental risk factor. Genetic (inherited) factors seem to influence the development of some neuroblastomas.

Symptoms of a neuroblastoma can include:

• A firm mass in the abdomen, with or without abdominal pain or discomfort
• Difficulty breathing (due to the abdominal mass pressing on the infant's chest and lungs)
• Weight loss or failure to gain weight (called failure to thrive)
• Anemia (a low number of red blood cells)
• Fever and irritability
• Bone pain
• Neurological symptoms if the tumor damages nearby nerves, including paralysis, difficulty swallowing, difficulty walking, uncontrolled eye movements, a drooping eyelid, or jerky or uncontrolled limb movements
• Protruding eyes or dark circles around the eyes ("panda eyes")
• Symptoms caused by chemicals produced by the tumor, including high blood pressure, rapid pulse, flushing, sweating or diarrhea

In some cases, a child's neuroblastoma is diagnosed by chance before it causes symptoms. The tumor is discovered in the chest or abdomen when the child has an X-ray to check for some unrelated illness.

Your doctor will review your child's symptoms and examine the child. The doctor will order blood and urine tests and X-rays. A computed tomography (CT) scan or magnetic resonance imaging (MRI) often is needed to provide further detail.

If any of these tests show signs of a cancerous (malignant) tumor, your doctor will refer you to a medical center that has the facilities, personnel and experience to treat childhood cancer. There, your child will have further tests to confirm the diagnosis of neuroblastoma. These may include a biopsy, in which a small piece of the tumor is removed and examined in a laboratory. A sample of bone marrow also may be taken.

In most cases, a neuroblastoma will continue to grow until it is treated. Without treatment, the cancer can spread to the bone marrow, bones, liver, skin and other parts of the body. A small number of neuroblastomas, usually in children less than 1 year old, decrease in size over time and do not need aggressive treatment.

There is no way to prevent neuroblastoma. However, because genetic factors seem to play some role in the development of this tumor, people with a strong family history of cancer -- especially childhood cancer -- might want to ask their doctors about the need for genetic testing before starting a family.

How a neuroblastoma is treated depends on how much it has spread. This is called the tumor stage. Tumor stage is determined by how much of the tumor can be removed surgically and whether the cancer has spread to nearby lymph nodes or to distant organs. Here are the stages of neuroblastoma:

• Localized neuroblastoma. This means the tumor has not spread. If the tumor is localized and can be removed completely with surgery, no additional treatment may be needed. If the tumor is localized but cannot be removed completely, the child will need chemotherapy. After chemotherapy, the child may need a second surgery to remove any remaining tumor. This may be followed by radiation therapy.



• Regional neuroblastoma. A regional neuroblastoma has spread to local lymph nodes or to nearby tissues or organs but has not spread to areas further away. A regional neuroblastoma is treated with a combination of surgery and chemotherapy. Older children also may receive radiation therapy.



• Disseminated neuroblastoma. A disseminated neuroblastoma has spread to distant organs or tissues. This is the most common stage at which children are diagnosed. This advanced stage can be treated with intensive chemotherapy, with or without surgery or radiation.



• Special neuroblastoma, also called stage IVS neuroblastoma. In this stage, the tumor is fairly localized, but some cancer has spread to the liver, skin or bone marrow. This stage usually appears in infants younger than 12 months. In most cases, children with tumors of this stage do very well. Treatment is controversial, however, with some doctors giving only mild chemotherapy and other doctors choosing a watch-and-wait approach.

Chemotherapy: There are a wide variety of chemotherapies that have been shown to increase the overall results and cure rates of children with neuroblastoma. As with other agents such as radiation, long-term follow up of children will be required to monitor the possibility of second cancer development and long-term damage to organs such as the kidney, heart and bone marrow.

Other investigational agents: Both vaccines and monoclonal antibodies to specific chemical located on the surface of the neuroblastoma cells have been used with some success in treating this disease. Oftentimes, children with the permission of their parents are encouraged to participate in clinical studies to help evaluate the most effective treatments.

Call your doctor if your child shows symptoms of neuroblastoma, especially if your child has an abnormal fullness or swelling in the abdomen. As with any pediatric tumor, it is imperative to seek the advice of a pediatric cancer specialist to ascertain that the most current and effective therapies are offered and that the complications of surgery, chemotherapy and radiation can be minimized. This is generally best accomplished in cancer centers with a focus on pediatric patients.

With treatment, up to 90% of children with localized neuroblastoma or special neuroblastoma can be cured. A genetic test is available to better estimate a child's prognosis. Neuroblastoma that has spread to the surrounding area or to other areas has a worse outlook. However, most children respond to treatment of this cancer even in advanced stages. Children with special neuroblastoma may do extremely well without any treatment, but they continue to need close observation by a specialist.

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