Objective: In California, leukemia represents ~35, 5, and 2% of all cancers in children (aged 0-14), adolescents (15-29), and young adults (30-39), respectively. Poorer survival has been previously noted in individuals residing in lower socioeconomic status (SES) neighborhoods. We explored the relationship between SES and survival as modified by age and race/ethnicity using data from the California Cancer Registry.
Methods: A total of 7,688 incident cases of first primary leukemia diagnosed during 1996-2005 in individuals aged 0-39 at diagnosis were included in this study. Univariate analyses of overall survival were conducted using the Kaplan-Meier method and multivariate survival analyses were performed using Cox proportional hazard regression to estimate hazard ratios.
Results: Multivariate analyses showed that overall survival and lymphoid cancer-specific survival was reduced in those individuals aged 15-39 compared to children aged 0-14. Although shorter survival was observed in non-whites, an association between lower-SES neighborhood and shorter survival was significant only for non-Hispanic whites (NHWs) (p value for trend <0.05). Lack of insurance was significantly associated with shorter survival for all race/ethnicities examined except Asian/Pacific Islanders (p value < 0.05).
Conclusion: Lower survival in individuals diagnosed with leukemia was observed in adolescents and young adults compared to children and in non-whites compared to NHWs. Further, the independent effects on survival of both low SES and lack of insurance at diagnosis persisted after adjustment for demographic variables and varied across race/ethnicities.