Trends in childhood cancer incidence in Wisconsin, 1980-1999.

OBJECTIVES Characterizing the burden of childhood cancer in Wisconsin is the first step to assessing the impact of prevention efforts, identifying especially vulnerable subgroups, and directing etiologic research. To support these goals, population-level data were used to examine trends in childhood cancer incidence among children aged 0-14 years in Wisconsin from 1980 to 1999. METHODS Data for Wisconsin was provided by the Wisconsin Cancer Reporting System and compared to national data. Annual age-adjusted childhood cancer incidence rates for the entire population and subgroups by age, sex, race, time period, diagnostic code, and geographic region were described. Correlational analysis was conducted to assess the relation between community socioeconomic status and childhood cancer incidence using census data. RESULTS Overall, Wisconsin's annual incidence rate for childhood cancers was 14.4 cases per 100,000 children aged 0-14 years during 1980-1999. This rate increased 10.9% (95% confidence interval 1-22%) between 1980 and 1999. Children in the 0-4 age group (20.9 per 100,000 per year) had the highest incidence rates as compared to 5-9 year olds (10.4 per 100,000 per year) and 10-14 year olds (12.0 per 100,000 per year). In males, the age-adjusted incidence of childhood cancers between 1980 and 1999 was 15.5 cases per 100,000 per year, whereas females had an incidence rate of 13.1 per 100,000 per year. Rates for whites were similar to the rates for all other racial groups combined. Leukemia had the highest age-adjusted incidence rate among childhood cancer diagnostic subtypes (4.3 cases per 100,000 per year); leukemia incidence increased by 32% between 1980 and 1999. Among the 13 hospital referral regions in Wisconsin with reported cancer cases, the Dubuque region had the highest annual age-adjusted incidence rate of 24.6 cases per 100,000, followed by Madison with 15.6 per 100,000, and Milwaukee with 15.5 per 100,000. In general, higher socioeconomic status as reflected by census indicators was positively correlated with higher rates of childhood cancer. SUMMARY Wisconsin experienced childhood cancer incidence rates and trends similar to those throughout the United States between 1980 and 1999. Analysis of Wisconsin data, which is subject to small numbers in absolute terms (3,138 cases during 1980-1999), suggests that not all children have similar risk--infants and younger children (<5 years of age) as well as children living in areas with higher socioeconomic status may be especially vulnerable.