The New Jersey Department of Health collects health-related data and uses it to do surveillance and research. This report is one of a series including data from the inception of the New Jersey State Cancer Registry through the most recent year data were available at the time of publication.
An estimated 8,700 children were diagnosed with cancer in the United States in 1998. Although the absolute number of cases is small compared to cases of adult cancer, cancer is the second leading cause of death for children under age 15, after fatal injuries. The most common childhood malignancies are leukemias and brain cancers.
Patterns of cancer incidence in children are very different than those in adults. For adults, carcinomas are the most common cell type, or histology. Carcinoma is a cancer deriving from the cells that line internal organs and the body surface. By contrast, most childhood cancers are of the cell type called sarcomas. Sarcoma is a cancer of connective tissue, such as bone, muscle and blood vessels. Most childhood cancers are thought to have some genetic influence.
The incidence rates of cancer in children under age 15 in the United States has been increasing at an estimated 0.8 percent per year from 12.8 per 100,000 in 1973-74 to 13.6 per 100,000 in 1994-95. The reasons for this increase are not known and are currently under study, but the trend is consistent with what has been seen in other industrialized countries such as England, Scotland, Germany, and Australia. Researchers have speculated that various factors may be responsible for the increased number of reported cases, including improvements in access to medical care, more complete case ascertainment by registries, new or more extensive environmental exposures, secondary cancers caused by the treatment of the initial cancer, or random variation.
By contrast, mortality rates for childhood cancer in the United States have declined from 5.4 per 100,000 in 1973-74 to 2.8 per 100,000 in 1994-95. This decline represents a 46% decrease in mortality. The largest declines in mortality have occurred for Hodgkin's lymphoma, soft tissue sarcoma, and leukemia (acute lymphocytic leukemia, in particular). These trends reflect dramatic successes in the treatment of childhood cancer.
Similarly, five-year survival rates have increased from 55.6 percent in 1974-76 to nearly 73.8 percent in 1989-94. For Hodgkin's lymphoma, the five-year survival rate increased from 79.0 percent in 1974-76 to 92.4 percent in 1989-94; for acute lymphocytic leukemia the five-year survival rate increased from 52.9 percent in 1974-76 to 80.2 percent in 1989-94; and for soft tissue sarcoma from 60.7 percent in 1974-76 to 76.0 percent in 1989-94.
For children with cancer, the long-term survival rates are of particular interest. However, current 10-year survival data are based on children diagnosed and treated with medical techniques from at least ten years ago. The 10-year survival rate for children diagnosed in 1985 is 64 percent, but that number is probably even higher now.