n WHAT CAUSES NEUROBLASTOMA? The cause of neuroblastoma is unknown. We do know, however, that it is not contagious and cannot be caught from another person. In very few instances, neuroblastoma may be caused by a change in the body’s genes that are passed from a parent to a child. Genes are forms of DNA. DNA is a collection of chemical information that carries instructions for making all the proteins a cell will ever need. However, it is extremely rare to have more than one person with neuroblastoma in a family. We also know that some infants are born with this cancer, which suggests that there is an accidental growth that occurs while the unborn child’s nerve cells are growing and maturing. The nerve cells remain immature and develop into neuroblastoma cells. Who Gets Neuroblastoma? Although neuroblastoma is the third most common type of cancer in children, it is still rare. Approximately 800 cases are diagnosed each year in the United States. In most cases, it is a disease of early childhood. About one third of children diagnosed with neuroblastoma are infants, and almost 90% of all children with neuroblastoma are younger than 5 years at diagnosis. Cases in children older than 10 years are extremely rare. What Is Metastasis? Metastasis refers to the spread of a tumor from its original location (primary site) to other parts of the body. Neuroblastoma metastasizes, or spreads, very easily, most commonly to the lymph nodes, bone and bone marrow (the inside of the bone where blood cells are made), liver, or skin. Neuroblastoma has been called a silent tumor because approximately 60% of children with this tumor already have metastases before any signs of the disease are noticed or diagnosed. What Is Staging and Risk Group Staging? Staging is the process of determining the location and amount of disease at the time of diagnosis. The International Neuroblastoma Staging System (INSS) divides neuroblastoma into four stages, ranging from a single tumor (stage 1) to a tumor plus disease that has spread to other parts of the body (stage 4). Another staging system, the International Neuroblastoma Risk Group (INRG), classifies your child’s disease as L1, L2, M, or Ms. In addition to determining the stage of neuroblastoma, your healthcare team will look at several additional factors to determine how aggressive the tumor is likely to be and determine the treatment your child will receive. These factors include the following: • whether the tumor is localized (a single tumor) or metastasized (spread to other parts of the body) • your child’s age at diagnosis • what the tumor looks like under the microscope • whether the tumor has more than 10 copies of the MYCN oncogene (a gene with the potential to cause cancer) • changes to chromosome 1p and 11q.
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