Racial and ethnic differences in survival of children with acute lymphoblastic leukemia

Abstract

Abstract Black children with acute lymphoblastic leukemia (ALL) have poor outcomes, but limited information is available for children from other racial and ethnic backgrounds, such as Hispanic and Asian. We undertook a retrospective cohort study of children with ALL treated on Children's Cancer Group therapeutic protocols to determine outcomes by racial and ethnic backgrounds of patients treated with contemporary risk-based therapy. In total, 8447 children (white, n = 6703; Hispanic, n = 1071; black, n = 506; and Asian, n = 167) with newly diagnosed ALL between 1983 and 1995 were observed for a median of 6.5 years. Analysis of disease outcome was measured as overall survival (OS) and event-free survival (EFS) and was adjusted for known predictors of outcome including clinical features, disease biology, socioeconomic status, and treatment era (1983-1989 vs 1989-1995). There was a statistically significant difference in survival by ethnicity (P < .001). Five-year EFS rates were: Asian, 75.1% ± 3.5%; white, 72.8% ± 0.6%; Hispanic, 65.9% ± 1.5%; and black, 61.5% ± 2.2%. Multivariate analysis revealed that when compared with white children, black and Hispanic children had worse outcomes and Asian children had better outcomes after adjusting for known risk factors. The poorer outcomes among black children were most apparent among patients with standard-risk features (relative risk [RR], 2.0; 95% confidence interval [CI], 1.6-2.5), whereas poorer outcomes in Hispanic children (RR, 1.4; 95% CI, 1.2-1.6) were most evident among patients with high-risk features. Asian children had better outcomes than all racial and ethnic groups among high-risk patients, particularly in the recent era (5-year EFS, 90.9% ± 6.1%). Racial and ethnic differences in OS and EFS persist among children with ALL who receive contemporary risk-based therapy. Future studies should focus on reasons—perhaps compliance or pharmacogenetics—for those differences.