Abstract B138: Examining factors that contribute to racial and ethnic disparities in liver cancer within an EHR-based epidemiologic cohort linked to cancer registries
Authors: DeRouen Mindy C. , Canchola Alison J. , Chu Janet , Cortella Aly , Inamdar Pushkar , Nie Sixiang , Vu Mai , Somsouk Ma , Tana Michele , Thompson Caroline A. , Gomez Scarlett L. , El-Serag Hashem , Kim Mi-Ok , Segal Mark , Ho Chanda , Daida Yihe G. , Liang Su-Ying , Shariff-Marco Salma 
Published: December 2023

Abstract
Background: Racial and ethnic disparities in HCC risk have been documented, but disparities across detailed racial and ethnic groups and the relative contribution of these factors to HCC risk across those groups has not been assessed. We assembled a pooled, EHR-based cohort linked to cancer registry data to study disparities in HCC risk among detailed racial and ethnic groups and to examine the relative contribution of known and putative HCC risk factors to disparities in risk. Methods: Adults with at least one in-person encounter in 2000-2017 within three healthcare systems, San Francisco Health Network, Sutter Health Northern California, and Kaiser Permanente Hawai’i, were linked to their respective population-based state cancer registries for data on incident HCC. We used EHR data to define 17 detailed racial and ethnic groups and other sociodemographic and clinical factors. We used Cox proportional hazards regression with age as the timescale to examine racial/ethnic disparities in HCC risk with sex-specific models adjusted for length of active follow-up and with underlying stratification by site, birth cohort, baseline year and number of encounters. We calculated sex-specific hazards and population attributable fractions (PAFs) of HCC risk factors among racial/ethnic groups (e.g., smoking, hepatitis infections, metabolic syndrome). Results: The pooled cohort contained data on 4,249,671 adults followed a median of 6.8 years; 55% were female, and 2,916 had incident HCC. Compared to non-Hispanic White males, Vietnamese American males had greater risk of HCC (HR: 7.42; 95% CI: 4.25, 12.96) as did American Indian/Alaska Native, Black, Chinese American, Hispanic, Native Hawaiian, and Pacific Islander males, and those of multiple races or ethnicities. Among females, every group except for American Indian/Alaska Native, Asian Indian American, and Pacific Islander females had greater risk of HCC compared to the non-Hispanic White group; HRs ranged from 1.68 (1.01, 2.78) among Filipino to 6.38 (2.79, 14.55) among Vietnamese American females. Risk of HCC according to clinical risk factors was similar for males and females; however, the PAF of HCC for alcohol disorders was much higher for females (43%) than males (2%). Analyses by racial/ethnic group are ongoing, but variation in factor-specific risk of HCC was observed in preliminary analyses; for example, only non-Hispanic White and Asian American males had greater risk of HCC with metabolic-associated fatty liver disease and ever-smoking. Conclusions: Analysis of a large EHR-based cohort linked with cancer registry data yields additional information on cancer disparities across detailed racial and ethnic groups and may benefit efforts to identify targets for intervention. Our results indicate disparities in HCC risk across detailed racial and ethnic groups traditionally aggregated into larger groups (e.g., Asian American/Pacific Islander). Variation in the PAF of HCC for known risk factors suggest that the most impactful prevention efforts may require tailoring to the target populations.
Citation Format: Mindy C. DeRouen, Alison J. Canchola, Janet Chu, Aly Cortella, Pushkar Inamdar, Sixiang Nie, Mai Vu, Ma Somsouk, Michele Tana, Caroline A. Thompson, Scarlett L. Gomez, Hashem El-Serag, Mi-Ok Kim, Mark Segal, Chanda Ho, Yihe G. Daida, Su-Ying Liang, Salma Shariff-Marco. Examining factors that contribute to racial and ethnic disparities in liver cancer within an EHR-based epidemiologic cohort linked to cancer registries [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 B138.