Differential inequality trends over time in survival among U.S. children with acute lymphoblastic leukemia by race/ethnicity, age at diagnosis, and sex.

BACKGROUND: It is unclear how inequalities in survival among children with acute lymphoblastic leukemia (ALL) have changed over time in different race/ethnicity groups.
METHODS: Children diagnosed with a first primary malignant ALL at ages 0 to 19 years in 1975-2010 in the nine Surveillance, Epidemiology, and End Results cancer registries were included. Cumulative ALL mortalities were compared, and multivariable Cox regression analyses were applied to estimate ALL mortality HRs associated with race/ethnicity, age at diagnosis, and sex, adjusting for each other, within each diagnosis period (1975-1983, 1984-1991, 1992-1999, and 2000-2010).
RESULTS: Compared with non-Hispanic-whites (NH-whites), the HR in non-Hispanic-blacks (NH-blacks) dropped to 1.21 [95% confidence interval (CI), 0.74-1.96] in 2000-2010 from the largest inequality in 1984-1991 (HR, 2.09; 95% CI, 1.57-2.79); the HR in Hispanics increased, however, from 1.28 (95% CI, 0.98-1.66) in 1975-1983 to 1.95 (95% CI, 1.48-2.58) in 2000-2010. Asian/Pacific Islanders (API) and American Indian/Alaska Natives (AIAN) had HRs of 1.39 (95% CI, 0.92-2.11) and 2.31 (95% CI, 1.13-4.74), respectively, in 2000-2010 with nonstatistically significant increases over time. In 2000-2010, compared with NH-white counterparts, NH-blacks and APIs diagnosed at 1-9 years, Hispanics diagnosed at 1-9 and 10-19 years, and AIANs diagnosed at 10-19 years all had about twice the ALL mortality hazard rates; inequality was observed among API boys (HR, 1.61; 95% CI, 1.00-2.60) but not API girls.
CONCLUSIONS: Survival inequalities changed differently across subgroups of children with ALL. IMPACT: Underlying causes of the differential trends need to be examined, such that targeted interventions can be developed to reduce inequalities. ©2015 American Association for Cancer Research.