Acute lymphoblastic leukemia (ALL) is the most common type of childhood cancer. While there have been successes in the treatment of leukemia, less information is available on reasons for disparities in event-free survival (EFS) among underserved populations.
We partnered with a children’s hospital at an academic institution to abstract data from the institution’s cancer registry, the state cancer registry, and electronic medical records on cancer diagnosis, treatment, and outcomes for children with ALL (n = 275) diagnosed from 2005 to 2019 prior to age 20. We evaluated the relation between 1) race/ethnicity, 2) distance to the children’s hospital, and 3) area deprivation with EFS, defined as time from diagnosis to relapse, death, or the end of the study period. We evaluated differences in EFS using Kaplan-Meier analysis with the log-rank test. We used the Cox Proportional Hazards Model for multivariable survival analyses.
Most children were diagnosed with ALL under five years of age (45%) and with Pre-B ALL (87%). Twelve percent of children experienced a relapse and 5% died during induction or remission. EFS at 5 years was 82%. Non-Hispanic (NH) Black children had worse, though imprecise, EFS compared to NH White children (Adjusted Hazard Ratio: 2.07, 95% CI: 0.80, 5.38). Children residing in areas with higher deprivation had a higher adjusted hazard of poor outcomes compared to the least deprived areas, though estimates were imprecise (2nd quartile HR: 1.51, 3rd quartile: 1.85, 4th quartile: 1.62). We observed no association between distance to the children’s hospital and EFS.
We observed poorer EFS for NH Black children and children residing in areas with high deprivation, though the estimates were not statistically significant. Our next steps include further evaluating socioeconomic factors in both rural and urban children to identify disparities in outcomes for children with ALL and other childhood cancers.
- • Children with acute lymphoblastic leukemia who have a relapse have poorer outcomes.
- • Underrepresented children had poorer, though imprecise event-free survival.
- • We observed no association between distance to care and event-free survival.
Childhood cancer is the leading cause of disease-related death among children aged 5–19 years in the US . Acute lymphoblastic leukemia (ALL) is the most common type of childhood cancer and has one of the highest 5-year survival percentages (90%) . The most common cause of poor outcome is relapse. Across treatment eras, survival after relapse has continued to be poor . Children who experienced an early bone marrow relapse (within 36 months of the first remission) had 3-year event-free survival (EFS) rates of 32% and overall survival of 43% in a study of children treated on cooperative group clinical trials from 1996 to 2000 .
Risk factors for poor outcomes among ALL patients include biologic prognostic factors (age at diagnosis, initial white blood cell count, subtype of ALL, sex, leukemia and germline chromosomal changes, and response to induction treatment), poor adherence to maintenance therapy, access to care, and socioeconomic status . Several studies across the world have observed poorer outcomes with increased distance to the cancer treatment facility among children with ALL and any childhood cancer . Regarding socioeconomic status, Bona et al. observed that children with ALL diagnosed from 2000 to 2010 who lived in high poverty ZIP Codes had a higher percentage of early relapse compared to children living in lower poverty ZIP Codes. Poorer socioeconomic status may increase the risk of non-adherence to treatment or be related to poorer overall health status .
Central cancer registries have limited data on cancer relapse since this is not a required variable for the National Program of Cancer Registries, which covers 46 states, DC and three territories and coordinates with the Statistics, Epidemiology and End Results registries. Thus, linkages with non-registry-based data sources are necessary to evaluate relapse and EFS . Most studies evaluated relapse from clinical trial data, which excludes those who declined participation in a trial and may differ systematically from those who choose to participate in a trial . Furthermore, clinical trial participation has declined in recent years for childhood cancer patients (20% participation rate among those diagnosed from 2004 to 2015 from approximately 54% in 1993) . Thus, a combination of data sources is needed to evaluate EFS among children with ALL.
To address these gaps, we linked electronic medical records (EMR), an institutional cancer registry, and state cancer registry data to evaluate outcomes among children with ALL at a single institution in Oklahoma, which is racially diverse and serves a large proportion of rural residents. Our objective was to evaluate demographic factors, including race/ethnicity, distance to care, and area deprivation with EFS among children diagnosed with ALL prior to age 20 from 2005 to 2019.