• Introduction
  • Total Childhood Cancer
  • Leukemias
  • Lymphomas
  • Nervous System Cancers
  • Kidney Cancers
  • Bone Cancers
  • Incidence Rates by County
  • Discussion
  • Childhood Cancer

    Chapter II

    Rates and Risk Factors
    for Specific Childhood Cancers


    The most common neoplasm of the soft tissue in children is rhabdomyosarcoma, followed by fibrosarcomas. Soft tissue refers to the soft connective or supporting tissues, such as muscle.

    Incidence Rates

    The incidence rate of soft-tissue sarcomas among NJ children was 0.9 per 100,000 during 1979-1995 (Table 1a). The corresponding rate for the US was 1.0 per 100,000. Rhabdomyosarcoma had an incidence rate of 0.5 per 100,000 NJ and US children. The incidence rate of rhabdomyosarcoma was slightly higher among boys (0.5 per 100,000) than among girls (0.4 per 100,000), but was the same for black and white children.

    Incidence and Mortality Trends

    Figure 12 shows the incidence and mortality trends for soft-tissue sarcomas. The numbers of these cancers are so low that differences of just one or two cases each year produces fluctuations in the graph seen in Figure 11 which cannot be interpreted as increasing or decreasing trends but rather as normal variation over time. The incidence rates for NJ and the US were essentially constant at about 1.0 per 100,000 throughout the period. The mortality rates for NJ and the US were stable at about 0.2 per 100,000.

    Figure 12

    Demographic Patterns

    Approximately two-thirds of rhabdomyosarcomas originate in tissues formed during the first two months of pregnancy. The incidence of rhabdomyosarcoma is higher for boys than for girls, and the rate among white children was slightly higher than among black children. The incidence of this cancer peaks at age five for boys and at age three for girls. The rates decline thereafter. The five-year survival rate for the soft-tissue sarcomas as a group is about 76 percent.2, 24

    Genetic Risk Factors

    Families with Li-Fraumeni syndrome experience an unusually high incidence of sarcomas. It is believed that up to ten percent of soft-tissue sarcomas can be attributed to this inherited syndrome. There are several other genetic disorders that predispose to sarcomas and which may occur as components of family cancer syndromes.6

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