Abstract 3671: Association between residence in a Hispanic enclave and end-induction minimal residual disease among children with acute lymphoblastic leukemia in Texas

Abstract Background: Acute lymphoblastic leukemia (ALL) remains a leading cause of death in children and adolescents. We have demonstrated that Hispanic enclaves - neighborhoods with high proportions of Spanish-speaking residents, recent immigrants, and ethnic-specific businesses - are associated with inferior overall survival in children with ALL. However, associations of enclaves with other outcomes remain poorly understood. In the present study, our objective was to determine whether residence in an enclave was associated with end-induction minimal residual disease (MRD), a strong predictor of ALL mortality. Methods: This was a retrospective study of N=142 children aged 0-18 years, treated at Texas Children’s Hospital (Houston, TX) from 2007-2018. MRD was defined as ≥0.01% leukemic blasts in bone marrow at day 29 of therapy. We used the 2010 census tract geography and a modified version of the Hispanic enclave index to identify enclaves. We assigned an enclave index score to each census tract, computed quartiles based on the statewide distribution, and mapped children to quartiles based on address at diagnosis (Q1: least ethnically distinct neighborhoods; Q4: most ethnically distinct neighborhoods). Data on sex, self-reported race/ethnicity, National Cancer Institute (NCI) risk group, primary language, and ALL cytogenetics were abstracted from electronic health records. Cytogenetics were considered either unfavorable (BCR-ABL1 fusion, KMT2A rearrangement, hypodiploidy, or intrachromosomal amplification of chromosome 21) or favorable (ETV6-RUNX1 fusion, double trisomies of chromosomes 4 and 10)/neutral (neither favorable nor unfavorable). We estimated the odds ratio (OR) and 95% confidence interval (95% CI) of MRD according to enclave index score using logistic regression. Results: Neither individual ethnicity nor primary language varied by MRD status, but a greater proportion of MRD-positive children lived in the most ethnically distinct neighborhoods (53% vs. 36%, p=0.04). Enclave index score was associated with MRD after adjusting for sex, NCI risk group, and cytogenetics (OR 1.57 per quartile increment, 95% CI 1.09-2.33). We also observed non-significantly increased odds of MRD among children in Q3 (OR 1.53, 95% CI 0.41-6.55) and Q4 (OR 2.84, 0.83-11.58) relative to Q1. Conclusions: We found that residence in a Hispanic enclave was associated with MRD in children with ALL. Neither ethnicity nor primary language differed by MRD status, suggesting that these did not confound the association with enclave index score. Neighborhood factors may influence early treatment outcomes in ALL, and children living in Hispanic enclaves may constitute a high-risk population. Citation Format: Joshua P. Muniz, John P. Woodhouse, Amy E. Hughes, Sandi L. Pruitt, Karen R. Rabin, Michael E. Scheurer, Philip J. Lupo, Jeremy M. Schraw. Association between residence in a Hispanic enclave and end-induction minimal residual disease among children with acute lymphoblastic leukemia in Texas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3671.