Racial/ethnic diversity in children's oncology clinical trials: ten years later

During the past 50 years, clinical trials have led to dramatic improvement in pediatric cancer survival. Prior studies have shown that racial/ethnic and age groups have not been enrolled proportionally. Whites, Hispanics, and adolescents are under-represented and black children are over-represented. This study identifies the current racial/ethnic/age/sex representation in pediatric (ages birth to 19 years) cancer treatment trials.

The authors compared the observed proportions (O) of US children enrolled in Children's Oncology Group (COG) clinical trials from 2000 through 2003 with expected proportions (E), based on Surveillance, Epidemiology, and End Results (SEER) data. The enrollees were subgrouped by race/ethnicity, age, sex, and cancer type (solid or lymphohematopoietic). Chi-square tests and 95% confidence intervals were used for O versus E comparisons.

Although representation was fairly proportional for each racial/ethnic group, significantly under-represented solid tumor subgroups were whites (males particularly), adolescents ages 10 to 19 years, and Hispanics aged <10 years. For lymphohematopoietic cancers, significantly under-represented subgroups were blacks, Hispanics, adolescents ages 10 to 19 years, blacks aged <10 years, Hispanics aged <5 years, white and black males, and black and Hispanic females. The most significantly under-represented groups were adolescents ages 15 to 19 years for both solid (9.1% O vs 34.3% E) and lymphohematopoietic (11.0% O vs 30.2% E) cancers and Hispanic females with lymphohematopoietic cancers (11.9% O vs 20.5% E). COG enrolled 26.8% of expected cancer cases.

Although racial/ethnic groups are proportionally represented in COG trials, some specific subgroups including the youngest black and Hispanic children, Hispanic females, and particularly white adolescents ages 15 to 19 years may be under-represented and may benefit from targeted attention.