Abstract A003: Decomposing racial and ethnic disparities in endometrial cancer survival
Authors: Brown Jordyn A. , Sinnott Jennifer A. , Gao Ziyu , Meade Caitlin E. , Donneyong Macarius M. , Padamsee Tasleem J. , Felix Ashley S. 
Published: March 2024

Abstract
Background: Black-White mortality disparities are well-established and continue to widen over time among women diagnosed with endometrial cancer (EC). Yet, few studies have explored the existence or sources of racial/ethnic disparities in EC survival among Hispanic, American Indian/Alaska Native (AI/AN), Asian, and Native-Hawaiian/Pacific Islander (NH/PI) women. EC survival disparities across racial and ethnic groups have been suggested to be linked to differences in sociodemographic, clinical, and access to care characteristics. We examined how these individual- and area-level factors influence the presence of racial/ethnic disparities among women with EC. Methods: Participants were diagnosed between 2004 and 2019 with stages 1A through 4B endometroid and non-endometroid EC in the National Cancer Database (NCDB). Race was categorized as non-Hispanic white (NHW), non-Hispanic black (NHB), Hispanic, Asian, NH/PI, and AI/AN. We performed Oaxaca-Blinder decompositions of the log overall survival (OS) time assuming an accelerated failure time model with Weibull error, which decomposes observed differences in log survival time into parts potentially explained by differences in measured prognostic factors and differences not explained by measured variables. We examined the following classes of prognostic factors: age at diagnosis, zip code-level demographics (educational attainment, average income, and rurality), access to care (insurance status, facility type and location, treatment delay), Charlson comorbidity score, tumor characteristics (stage and histology), and guideline-concordant treatment (GCT). White women were the comparison group in all decompositions. Results: Compared with NHW women (N=121,069; estimated overall survival for average covariates values (eOS)=19.7 years) eOS was significantly shorter among NHB women (N=15,855; eOS=9.9 years); longer among Asian women (N=5,098; eOS=42.7 years); longer among Hispanic women (N=9,671; eOS=25.9 years); and not significantly different in NH/PI (N=536; eOS=24.8 years) or AI/AN women (N=551; eOS=17.0 years). Measured covariates explained 76.7% of the difference for NHB women (p&lt;0.001); 19.7% for Asian women (p&lt;0.001); and did not significantly explain the difference for Hispanic women (8.4%; p=0.14). Factors significantly contributing to the observed differences for NHB women were tumor characteristics (61.5%); access to care (6.6%); zip code-level demographics (5.1%); comorbidity (3.9%); age (-1.8%); and GCT (1.5%). Significant factors for Asian women were age (16.6%); tumor characteristics (-6.0%); zip code-level demographics (4.7%); access to care (3.0%); and comorbidity (1.6%). Significant factors for Hispanic women were age (45.2%); tumor characteristics (-17.9%); access to care (-13.4%); comorbidity (-2.0%); and GCT (-1.0%). Conclusions: Contributors to EC survival disparities vary by race/ethnicity and strongly implicate the need for research to identify how disparities arise to tailor interventions to reduce survival gaps.
Citation Format: Jordyn A. Brown, Jennifer A. Sinnott, Ziyu Gao, Caitlin E. Meade, Macarius M. Donneyong, Tasleem J. Padamsee, Ashley S. Felix. Decomposing racial and ethnic disparities in endometrial cancer survival [abstract]. In: Proceedings of the AACR Special Conference on Endometrial Cancer: Transforming Care through Science; 2023 Nov 16-18; Boston, Massachusetts. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(5_Suppl):Abstract nr A003.