Abstract 982: Disparities in allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia are increasing

Abstract Introduction: Acute myeloid leukemia (AML) is the most prevalent form of leukemia. Allogeneic hematopoietic cell transplantation (allo-HCT) is the most effective and often the only curative treatment. Due to advancements in donor selection, a suitable donor is available for nearly all patients, and this may have remediated the previously reported disparities in allo-HCT based on race and ethnicity. To date, no studies have comprehensively examined allo-HCT rates and trend disparities after expanded donor availability. Therefore, this study aimed to identify and quantify trends in allo-HCT rates and disparities among different racial and ethnic groups. We hypothesized that transplant disparities have decreased over time between those identified as racial and ethnic minorities and non-Hispanic Whites (NHWs). Methods: Data on AML patients diagnosed from 2004 to 2021 were obtained from the National Cancer Database Participant User Data File. Utilizing a multiple linear regression model with a difference-in-differences approach, we calculated the annual absolute change in allo-HCT rates and corresponding p-values across racial and ethnic groups to compare trends in allo-HCT rates adjusted for covariates. Results: Over the study period, non-Hispanic Asian or Pacific Islanders (NHAPIs) exhibited the highest allo-HCT rate at 20.9%, starting at 12.1% in 2004 and influenced by an outlier increase to 34.0% in 2021. NHWs had the second highest rate of 19.7%, increasing from 9.1% in 2004 to 22.9% in 2021. The allo-HCT rate for Hispanics increased from 9.4% in 2004 to 24.3% in 2021; however, a period of low rates from 2006 to 2011 resulted in a lower overall allo-HCT rate of 15.9%. Non-Hispanic Blacks (NHBs) had the lowest allo-HCT rate at 9.8%, with an increase from 2.3% in 2004 to 11.5% in 2021. From 2004 to 2021, the annual percentage increase in allo-HCT in NHBs was estimated at 0.41% lower than NHW (95% Confidence Interval [CI]: -0.61%, -0.21%; p<0.01). Hispanics also had a statistically significant 0.27% lower annual increase in allo-HCT rate compared to NHW (95% CI: -0.51%, -0.03%; p=0.03). Although NHAPI exhibited a higher overall allo-HCT rate compared to NHW, the annual rate increase was 0.23% lower than NHW (95% CI: 0.55%, 0.09%; p=0.16), which reduced the differences in allo-HCT rates between these groups over the study period. Conclusion: NHB and Hispanics exhibited lower overall allo-HCT rates than NHW from 2004 to 2021, with evidence of widening disparities. NHAPI had overall higher allo-HCT rate than NHW, but the difference narrowed over time as NHW patients experienced a steeper increase in allo-HCT rates. These results suggest that despite the availability of suitable allo-HCT donors, not all patients have benefited equally. Further research is needed to investigate individual and systemic factors associated with allo-HCT disparities among racial and ethnic minorities. Citation Format: Lixin Kang, Mark A. Fiala, Kimberly J. Johnson. Disparities in allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia are increasing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 982.