Neuroblastoma

Definition

Neuroblastoma is a solid cancerous tumor that usually originates in the tissues of the adrenal gland, which is located in the abdomen near the kidneys. Tumors develop in the nerve tissue in the neck, chest, abdomen, or pelvis.

Description

Neuroblastoma occurs most often in children; it is the fourth most common cancer that occurs in children, affecting one in 100,000 children in the United States each year. Approximately 60% of cases of neuroblastoma occur in children younger than two years old, and 70-90% occur in children under the age of five years. The disease is sometimes present at birth, but is usually not noticed until later. By the time the disease is diagnosed, it has often spread to the lymph nodes, liver, lungs, bones, or bone marrow.

A staging system has been developed for neuroblastoma to help the physician determine how best to treat the disease. The staging system is based on how far the disease has spread from its original site to other tissues in the body. Localized resectable (able to be cut out) neuroblastoma is confined to the site of origin, with no evidence that it has spread to other tissues, and the cancer can be surgically removed. Localized unresectable neuroblastoma is confined to the site of origin, but the cancer cannot be completely removed surgically. Regional neuroblastoma has extended beyond its original site, to regional lymph nodes, and/or surrounding organs or tissues, but has not spread to distant sites in the body. Disseminated neuroblastoma has spread to distant lymph nodes, bone, liver, skin, bone marrow, and/or other organs. Stage IV's (or "special") neuroblastoma has spread only to liver, skin, and/or, to a very limited extent, bone marrow. Recurrent neuroblastoma means that the cancer has come back, or continued to spread after it has been treated. It may come back in the original site or in another part of the body.

Causes & symptoms

The most common symptoms of neuroblastoma arise because of pressure caused by the tumor and bone pain from cancer that has spread to the bone. Cancer that has spread to the area behind the eye may cause protruding eyes and dark circles around the eyes. Paralysis may result from compression of the spinal cord. Fever, anemia, and high blood pressure occur occasionally. Some children may have watery diarrhea, uncoordinated or jerky muscle movements, or uncontrollable eye movements, but these symptoms are rare.

Diagnosis

After the physician has performed a physical examination, he or she may use a scanning technique to confirm the diagnosis of neuroblastoma. These include computed tomography scan (CT scan) and magnetic resonance imaging (MRI). The physician may find it necessary to surgically remove some of the tissue from the tumor or bone marrow (biopsy), and examine the cells under the microscope.

Once neuroblastoma has been found, the physician will perform more tests to determine if the cancer has spread to other tissues in the body. This process, called staging, is important for the physician to determine how to treat the cancer.

Treatment

Treatments are available for children with all stages of neuroblastoma. More than one of these treatments may be used, depending on the stage of the disease The four types of treatment used are:

• Surgery (removing the tumor in an operation).
• Radiation therapy (using high-energy x-rays to kill cancer cells).
• Chemotherapy (using drugs to kill cancer cells).
• Bone marrow transplantation (replacing the patient's bone marrow cells with those from a healthy person).

Surgery is used whenever possible, to remove as much of the cancer as possible, and can generally cure the disease if the cancer has not spread to other areas of the body. Radiation therapy is often used after surgery; high-energy rays (radiation) are used to kill as many of the remaining cancer cells as possible. Chemotherapy (called adjuvant chemotherapy) may also be used after surgery to kill remaining cells. Also, before surgery, chemotherapy is used to shrink the tumor so that it can be more easily removed during surgery; this is called neoadjuvant chemotherapy. Bone marrow transplantation is used to replace bone marrow cells killed by radiation or chemotherapy. In some cases the patient's own bone marrow is removed prior to treatment and saved for transplantation later. Other times the bone marrow comes from a "matched" donor, such as a sibling.

Prognosis

The chances of recovery from neuroblastoma depend on the stage of the cancer, the age of the child at diagnosis, the location of the tumor, and the state and nature of the tumor cells evaluated under the microscope. Infants have a higher rate of cure than do children over one year of age, even when the disease has spread. In general, the prognosis for a young child with neuroblastoma is good: the predicted five year survival rate is approximately 85% for children who had the onset of the disease in infancy, and 35% for those whose disease developed later.

Prevention

Neuroblastoma may be a genetic disease passed down from the parents. There is currently no known method for its prevention.

Key Terms

Adjuvant chemotherapy

Treatment of the tumor with drugs after surgery to kill as many of the remaining cancer cells as possible.

Biopsy

A small sample of tissue removed from the site of the tumor to be examined under a microscope.

Disseminated

Spread to other tissues.

Localized

Confined to a small area.

Neoadjuvant chemotherapy

Treatment of the tumor with drugs before surgery to reduce the size of the tumor.

Resectable cancer

A tumor that can be surgically removed.

Staging system

A system based on how far the cancer has spread from its original site, developed to help the physician determine how best to treat the disease.

Unresectable cancer

A tumor that cannot be completely removed by surgery.

Further Reading

For Your Information

Books

• Raghaven, Derek, et al, eds. Principles and Practice of Genitourinary Oncology. Philadelphia: Lippincott-Raven Publishers, 1997.

  Periodicals

• Debatin, Klaus-Michael. "Cytotoxic Drugs, Programmed Cell Death, and the Immune System: Defining New Roles in an Old Play." Journal of the National Cancer Institute 89 (June 4, 1997): 89.
• Krakoff, Irwin H. "Systemic Treatment of Cancer." Cancer 46 (May 15, 1996): 134.
• Pearn, John. "Childhood and Adolescence; Recent Advances in Paediatrics, Part 2." British Medical Journal 314 (April 12, 1997): 1099.
• Sidransky, David. "Nucleic Acid-Based Methods for the Detection of Cancer." Science 278 (November 7, 1997): 1054.
• Strollo, Diane C., Melissa L. Rosado-de-Christenson, and James R. Jett. "Tumors of the Middle and Posterior Mediastinum; Primary Mediastinal Tumors, Part 2." Chest 112 (November, 1997):
• "Test Identified for Effective Treatment For Infants with Cancer: Neuroblastoma Diagnosis." Cancer Weekly Plus (March 17, 1997): 19.
• "Therapies Prove Value in Clinical Trials: Monoclonal Antibody Therapies." Cancer Weekly Plus (May 13, 1996): 13.

  Organizations

• National Cancer Institute. Office of Cancer Communications, 31 Center Drive, MSC 2580, Bethesda, MD 20892-2580. 800-422-6237. http://cancernet.nci.nih.gov/clinpdq/pif/Neuroblastoma_Patient.html.

Gale Encyclopedia of Medicine. Gale Research, 1999.