Abstract C075: Socioeconomic status and genetic ancestry correlate with differences in clinical outcomes for colorectal cancer patients treated at a single tertiary cancer center
Authors: Agbamu Tejiri , Bai Xuechun , Walch Henry , Waters Michele , Luthra Anisha , Arora Kanika , Fong Christopher , Rose Doori , Williams Hannah , Berger Michael , Ganesh Karuna , Garcia-Aguilar Julio , Schultz Nikolaus , Yaegar Rona , Chatila Walid , Sanchez-Vega Francisco 
Published: December 2023

Abstract
Intro: Lower socioeconomic status (SES) and African ancestry have been linked to poor overall survival (OS) in colorectal cancer (CRC). To better understand the interplay between these variables, we analyzed clinical and genomic real-world data from a large cohort of patients treated at a single tertiary center. Methods: Clinical annotations including sex, primary tumor location, age and stage at diagnosis were extracted from the electronic health record for 3,817 CRC patients who underwent clinical genomic sequencing at Memorial Sloan Kettering Cancer Center between 2014 and 2022. We also cataloged each patient’s type of primary health insurance (commercial, Medicare, Medicaid or self-pay). Socioeconomic status was assessed from each patient’s billing address using the Yost index (YI), which is a location-dependent percentile score based on household incomes, house values, rent, poverty, education, and employment statistics. Genetic ancestry was determined from DNA sequencing data using reference populations from the 1000 Genomes project, including European (EUR), African (AFR), East Asian (EAS), and Southeast Asian (SAS). Specific ancestries were assigned based on an ancestral fraction of &gt;80%, otherwise patients were labeled as admixed (ADM). OS was measured from time of diagnosis to last follow-up. Results: Our cohort included 2,627 EUR, 195 EAS, 206 AFR, 61 SAS and 728 ADM patients. The median YI within our cohort was 18 [IQR: 30]. No significant associations were observed between YI and primary tumor location, age or stage at diagnosis. We observed significant differences in YI based on type of health insurance (median 15 for commercial vs. 29 for Medicaid, p&lt;0.0001) and sex (median 15 in males vs. 17 in females, p=0.0113). YI was also strongly associated with genetic ancestry, with AFR patients exhibiting significantly higher YI values than other ancestries (median 45.5 vs. 14, p&lt;0.0001). No significant differences in YI were observed among EUR, EAS and SAS patients. When all ancestries were analyzed together, patients within the bottom YI quartile (most affluent) had significantly longer OS than patients from the top YI quartile (most deprived) (median 52.3 vs. 61.6 months, p=0.023). No differences in OS were observed between EUR, EAS and SAS patients, but patients of AFR ancestry had significantly shorter OS than the rest (median 44.5 vs. 56.5 months, p= 0.016). When the analysis was restricted to patients of EUR, EAS and SAS ancestry, OS was still significantly shorter for patients within the top vs. bottom YI quartile (median 52.6 vs. 64.4 months, p=0.011). Conclusions: Patients of African ancestry exhibited lower socioeconomic status and shorter survival. Even when the analysis was restricted to other genetic ancestries, patients with the lowest socioeconomic status still had poorer clinical outcomes. The existence of these differences within a relatively homogeneous cohort of patients treated at the same institution highlights the need to better understand and address health disparities in CRC.
Citation Format: Tejiri Agbamu, Xuechun Bai, Henry Walch, Michele Waters, Anisha Luthra, Kanika Arora, Christopher Fong, Doori Rose, Hannah Williams, Michael Berger, Karuna Ganesh, Julio Garcia-Aguilar, Nikolaus Schultz, Rona Yaegar, Walid Chatila, Francisco Sanchez-Vega. Socioeconomic status and genetic ancestry correlate with differences in clinical outcomes for colorectal cancer patients treated at a single tertiary cancer center [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C075.