Rates and Risk Factors
Rates and Risk Factors
This report presented childhood cancer incidence and mortality data for New Jersey and the United States for the period 1979 to 1995 (1994 for the United States). The purpose of this report is to make the data available to New Jersey residents and to assist health officials and other health providers. The most common cancer diagnoses in children under age 15 in both New Jersey and the United States were leukemias, central nervous system tumors, and lymphomas. For these cancers, and most others, the incidence rates among males were higher than among females and among whites were higher than among blacks.
Total childhood cancer incidence in New Jersey and the United States increased slightly between 1979 and 1995 (1994 for the United States). New Jersey incidence rates were slightly higher than the corresponding United States incidence rates. The differences between New Jersey and United States incidence rates narrowed over the period. The reasons for increased childhood cancer incidence are not completely understood, but researchers have speculated that a number of factors may be involved, such as 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.
Total childhood cancer mortality rates declined in New Jersey and the United States during the period. Mortality rate trends in New Jersey were very close to the corresponding United States rates and, for several cancers, were lower during more recent years than the United States mortality rates. The reduced mortality rates are due to improved treatment of childhood cancers.
The trends in childhood cancer incidence within individual counties for the most common cancers (leukemia, lymphocytic leukemia, and central nervous system) were presented for the period 1979 through 1995. For less common childhood cancers (lymphoma, Hodgkin's lymphoma, non-Hodgkin's lymphoma, kidney, bone, soft tissue), rates were given for the entire period combined. At the county level, the numbers of cancer cases and the population reflected in each rate were very small, resulting in rates that fluctuate even when there are only small changes in the numbers of cases. County rates were included to assist health officials and other health providers to estimate pediatric cancer service needs in their counties.
The risk factors for each cancer vary. Discussions of risk factors in this report largely follow what has been presented in National Cancer Institute and American Cancer Society publications and in review articles by recognized authorities on childhood cancer. When an individual study has been particularly important in understanding a risk factor, we cited that study. For several cancers, little has been published regarding risk factors. More research is needed on the causes and ways to prevent childhood cancers.