Colorectal Cancer Disparities Research Articles

Abstract C156: Examining the role of T cell responses in colorectal cancer sex disparities

Abstract Purpose: Persistent sex disparities in colorectal cancer (CRC) incidence and mortality exist and vary by race and ethnicity. The overarching goal of this proposal is to quantify differences in the CRC tumor immune microenvironment by sex in the Latino Colorectal Cancer Consortium (LC3). Methods: The LC3 is a consortium of pooled individual-level data from Latino participants diagnosed with CRC from California, Florida, and Puerto Rico. Biospecimens, epidemiologic data, and clinical outcomes were collected from each contributing study. DNA was extracted from tumor tissue and paired germline or normal tissue samples. Whole exome sequencing was performed using established protocols. Global genetic ancestry was estimated from whole exome sequence data. High-throughput T cell receptor (TCR) sequencing was used to estimate features of the T cell receptor (TCR) repertoire (e.g. abundance, clonality), and tumor-infiltrating lymphocyte (TIL) counts were obtained through pathology review. We evaluated differences in TCR abundance and TILs by sex using linear models for continuous measurements and generalized linear models for binary or count measurements. Primary analyses were unadjusted, and secondary analyses adjusted for age at diagnosis, stage at diagnosis, tumor location (right colon vs. left colorectum), and microsatellite instability (MSI) status. To examine how genetic ancestry modified the relationship between sex and T cell responses, we fit separate models with an interaction term between each genetic ancestry proportion variable (i.e. African, European, Native American) and sex, and assessed effect modification using a likelihood ratio test. Results: To date, 240 participants had TCR repertoire profiling and whole exome sequencing data generated. 52% were male, with a mean age of 58. 17% of participants had rectal tumors. With respect to Hispanic ethnic heritage or country of origin, 49% of participants were of Mexican descent, followed by 13% of Central or South American descent, and 10% were of Puerto Rican descent. Mean T cell abundance was 0.18 (standard deviation (SD): 0.16) and mean clonality was 0.05 (SD: 0.05). Further analysis is underway. Conclusions: This project leverages within-Latino genetic diversity to disentangle the contributions of sex and genetic ancestry to variability in immune function and to understand how this may further sex disparities in CRC. We anticipate that results from this analysis will provide insight on the relationship between the tumor immune microenvironment and sex disparities in CRC. Citation Format: Nicole C. Loroña, Ya-Yu Tsai, Daniel Sobieski, Eric Cockman, Stephanie L. Schmit, Jane C. Figueiredo. Examining the role of T cell responses in colorectal cancer sex disparities [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C156.

Abstract B152: Joint Associations of Neighborhood Socioeconomic Status and Education on the Incidence of Colorectal Cancer: The Multiethnic Cohort Study

Abstract Background: Colorectal cancer (CRC) is the 3rd most diagnosed cancer worldwide. When considered separately, both neighborhood- and individual-level SES exposures have been associated with CRC incidence. However, the joint associations of neighborhood- and individual-level SES on CRC incidence have not been examined. Methods: In a prospective study of 153,725 Multiethnic Cohort (MEC) participants (24,764 African American, 44,447 Japanese American, 34,974 Latino, 11,511 Native Hawaiian, and 38,029 White participants) recruited from predominantly Los Angeles County, California (CA), and Hawaii (HI), we examined the joint association of neighborhood SES (nSES) and individual-level education with CRC incidence (CA: 2,519, HI: 2,210 cases). Education, other demographics, and health behaviors were self-reported in the baseline questionnaire (1993-1996). CRC diagnosis was determined via linkages with state cancer registries. nSES was derived using a composite score based on 1990 US Census block group data and assigned to geocoded baseline addresses. Our joint SES measure included four categories: high nSES (quintiles 4-5) and high education (> high school), high nSES and low education (≤ high school), low nSES (quintiles 1-3) and high education, and low nSES and low education. State-specific hazards ratios (HR) for CRC incidence were estimated for joint SES categories. Cox regression adjusted for age at cohort entry, CRC family history, polyp history, obesity, diabetes, diet, alcohol, smoking, physical activity, and NSAID, multivitamin, and hormone therapy use. Subgroup analyses were conducted by sex, race, and ethnicity. Results: For HI MEC participants, compared to individuals with high nSES and high education, risk for CRC was highest among those with low nSES and low education (HR=1.27; 95% CI:1.11-1.45) followed by high nSES and low education (HR=1.25; 95% CI:1.12-1.41), and low nSES and high education (HR=1.17; 95% CI: 1.03-1.31). This pattern of association was observed across sex but differed across race and ethnicity (p-heterogeneity=0.04). The overall pattern of association was observed among White participants in HI. However, for Japanese American individuals in HI, compared to those with high nSES and high education, risk for CRC was highest for low nSES and high education (HR=1.29; 95% CI:1.09-1.53) and high nSES and low education (HR= 1.28; 95% CI; 1.10-1.50). For Native Hawaiian individuals, compared to those with high nSES and high education, CRC risk was highest for those with low nSES and low education (HR=1.70; 95% CI: 1.20-2.42). Associations were not statistically significant between the joint SES measure and CRC risk in CA (HRs: 0.92-0.97). Conclusion: Among MEC participants in HI, CRC risk varied with the joint measure of nSES and education across racial and ethnic groups. These findings emphasize the importance of considering the joint associations of neighborhood- and individual-level SES in understanding racial and ethnic disparities in CRC. Citation Format: Catherine Walsh, Meera Sangaramoorthy, Songyi Park, Sung-shim (Lani) Park, Gertraud Maskarinec, Lynne Wilkens, Christopher Haiman, Anna Wu, Salma Shariff-Marco, Loic Le Marchand, Iona Cheng. Joint Associations of Neighborhood Socioeconomic Status and Education on the Incidence of Colorectal Cancer: The Multiethnic Cohort Study [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr B152.

Abstract C129: Adapting to disruption?: Changes in colorectal cancer screening modalities and disparities during the COVID-19 pandemic

Abstract Research Objective: At-home colorectal cancer screening methods, such as Fecal Immunochemical Tests (FIT), offered a safer, convenient alternative to in-clinic procedures like colonoscopies during the COVID-19 pandemic. Racial and ethnic minorities were more likely to use these tests prior to the pandemic, but it is unclear whether disparities in colorectal cancer screening changed because of the pandemic. We examined rates of colorectal cancer screening before and after shutdown periods across race/ethnicity, age, and income among health plan enrollees in the United States to inform screening catch-up strategies after COVID-19 disruptions. Study Design: We conducted a retrospective analysis of cancer screening claims from Optum Clinformatics Data Mart among enrollees from 2019-2021. Monthly screening volume was calculated for a three-year period, with January 2019-February 2020 as the pre-pandemic period, and July 2020-December 2021 as the post-pandemic period. We conducted an event study to calculate group-level monthly predicted probabilities of screening using a linear probability model with group interactions by month, controlling for demographic variables and comorbidities. Additionally, we used difference-in-difference (DD) regressions including group interacted with a post-pandemic dummy. The pandemic closure period months were excluded from our DD analysis. Eligible enrollees included those ages 40-75 with continuous enrollment 12 months prior to screening index month. Colorectal cancer screening claims included codes for colonoscopies and other endoscopic procedures as well as FIT and FOBT tests. Results: 2,576,760 health plan enrollees were included. Colonoscopy rates did not change significantly between the pre-COVID period and post-COVID period, however FIT test screening rates dropped from an average of 0.66% of age-eligible enrollees screened per month in the pre-pandemic period to 0.58%. Our difference-in-difference results suggested Hispanic-NH White disparities in FIT tests widened. For colonoscopy, Hispanic-NH White and Asian-White disparities widened, while Black-White disparities decreased. Conclusions: Despite the promise that in-home FIT testing would substitute for colonoscopy during the pandemic, we saw a much larger decline in FIT testing rates during the pandemic than for colonoscopy and increasing disparities. This study highlights the need for targeted strategies to address screening disparities exacerbated by the COVID-19 pandemic, particularly among Hispanic and NH-Asian populations. Citation Format: Cameron M. Kaplan, Willow Pastard, John Thacker, Todd Schneberk, Chun Nok Lam, Sarah Axeen, Jennifer Tsui. Adapting to disruption?: Changes in colorectal cancer screening modalities and disparities during the COVID-19 pandemic [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C129.

Abstract A038: Uncovering the role of social determinants of health in racial disparities in cancer incidence in Alabama

Abstract Purpose Black-White racial disparities have long been recognized in cancer incidence. National estimates may not reflect racial disparities in individual states. In Alabama (AL), a primarily rural underserved state, Black Americans are more often diagnosed with breast, prostate and colorectal cancer (CRC), with Black men more often diagnosed with lung cancer. Although rurality and area-level deprivation, as social determinants of health (SDoH), have been associated with cancer, their role in explaining racial disparities in cancer incidence remains unknown. We assessed racial disparities in breast, prostate, CRC and lung cancer incidence in AL. Methods We used the Alabama Statewide Cancer Registry (ASCR) to collect data on incident cases of breast, prostate, CRC and lung cancers diagnosed between January 1, 2010 and December 31, 2019. We categorized cases according to age group (0-14, 15-19, 20-24, 25-34, 35-44, 45-64, 65-84, ≥85 years), racial/ethnic group (non-Hispanic Black/White), rural-urban status (defined by AL Rural Health Association), and national area deprivation index (ADI) quartile (Q1-Q4) of census tract at diagnosis. For each combination of these variables, we calculated age-adjusted incidence per 100,000. We conducted bivariate descriptive analysis of incidence rates by race, and rural-urban status and ADI quartile stratified by race. Results Incidence of breast, prostate and CRC cancer was higher in Black versus White individuals (breast 143 vs 127; prostate 206 vs100; CRC males 57.2 vs 45.4, CRC females 42.7 vs 32.6). Lung cancer incidence was higher in Black males and White females (Black vs White: males 82.7 vs 77.6; females 36.9 vs 49.9). In all cancers, racial differences in incidence existed by rural versus urban status (breast Black 142 vs 144, breast White 131 vs 124; prostate Black 204 vs 207, prostate White 101 vs 99.4; male CRC Black 60 vs 55.3, male CRC White 47.7 vs 43, female CRC Black 43.5 vs 42.3, female CRC White 35.2 vs 30.2; male lung Black 84.5 vs 81.7, male lung White 85.1 vs 70.2, female lung Black 31.4 vs 40.1, female lung White 54.4 vs 45.6). In all cancers, racial differences in incidence also existed by ADI status (reporting Q1 vs Q4) [breast Black 190 vs 130, breast White 144 vs 118; prostate Black 269 vs 189, prostate White 109 vs 101; CRC male Black 64.2 vs 56.7, CRC male White 41.2 vs 49.7, CRC female Black 43.4 vs 43.5, CRC female White 29.5 vs 36.6; lung male Black 73.7 vs 91, lung male White 57.9 vs 97.6, lung female Black 41 vs 37.7, lung female White 40.8 vs 60.7]. Conclusions In AL, racial differences in incidence rates for each of the most common cancers exist overall and by key SDoH. Generally, Black individuals have higher rates of cancer, particularly those in rural and low ADI areas. Next, we will perform a decomposition analysis to decompose the Black/White differences in incidence into a portion explained and unexplained by rural-urban status and ADI. Ultimately, these results may inform interventions in a rural underserved state with a large Black population at higher risk of cancer. Citation Format: Mackenzie E. Fowler, Hayden Reeves, Melissa J. Smith, Geetanjali Saini, Mahak Bhargava, Ritu Aneja. Uncovering the role of social determinants of health in racial disparities in cancer incidence in Alabama [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr A038.

Abstract A080: Improving outcomes: Addressing racial and ethnic disparities in colorectal cancer genomic research

Abstract Colorectal cancer (CRC) is the fourth most common cancer diagnosed in the United States (U.S.). This disease presents notable health disparities among racial and ethnic minorities in the U.S. Native Americans (NA) and non-Hispanic Blacks (NHB) exhibit the highest incidence and mortality rates for CRC compared to non-Hispanic Whites (NHW). These disparities are driven by a combination of factors, including socioeconomic inequalities, access to healthcare, lifestyle habits, and genetic susceptibilities. Minority populations often face delays in diagnosis and treatment, leading to advanced disease stages at presentation and poorer outcomes. Addressing these disparities through cancer genomics is essential for developing effective, personalized treatments that can improve outcomes for underrepresented populations. Comprehensive genomic studies can reveal genetic mutations and biomarkers unique to these groups, facilitating targeted therapies and preventive measures tailored to their specific needs. To address these disparities, we conducted an analysis of U.S. population-based colorectal cancer studies within 3 cancer genomic databases: the National Cancer Institute’s Genomic Data Commons, the AACR Project GENIE, and cBioPortal. We identified 13 studies suitable for inclusion, calculating incidence percentages across all racial and ethnic categories. Our analysis encompassed a total of 20,295 patients. Among the analyzed patients, the racial distribution was as follows: NHW (68.5%), Asians (5.30%), NHB (7.7%), Other (5.6%), NA (0.2%), Pacific Islander/Native Hawaiian (0.07%), and not reported (12.7%). Ethnic data was missing for 24.1% (n=4,895) of the patients. Samples were predominantly from individuals identified as Not Hispanic (68.4%), while Hispanic individuals constituted 7.5%. Our results show significant underrepresentation of NHB, NA and Hispanic patients in CRC genomic databases highlighting a disparity between expected and actual representation. These findings underscore the critical need for inclusive research practices. Addressing these disparities in cancer genomics is imperative to develop equitable, effective treatments and improve health outcomes for all populations. Ensuring diverse representation in genomic databases will enhance the understanding of genetic differences across populations, inform targeted therapies, and ultimately contribute to reducing CRC disparities. By addressing these disparities, we can move towards a future where all populations benefit equally from advancements in CRC treatment and prevention, thus improving survival rates and quality of life for minority groups. Citation Format: Gabriela Arroyo Figueroa, Tim F. Greten, Cecilia Monge. Improving outcomes: Addressing racial and ethnic disparities in colorectal cancer genomic research [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr A080.

Abstract C110: The role of the S100 family signaling pathway proteins in Hispanic colorectal cancer disparities

Abstract Colorectal cancer (CRC) is a global health concern, ranking as the second deadliest and third most diagnosed cancer. In the United States alone, it is estimated that there will be 152,810 new cases of CRC in 2024. CRC has an overall survival rate of 90% when detected in its early stages (Stage I/II). However, due to low screening rates, only 39% of CRC patients in the U.S. are diagnosed during the early stage, particularly among the minority groups like Hispanics. This disparity can be attributed to various factors, including limited access to health care facilities and socio-economic barriers. Among Hispanics, CRC diagnosis and screening rate are lower, resulting in a higher incidence of late-stage (Stage III/IV) diagnosis compared to Non-Hispanic Whites (NHW). Only 33% of Hispanics receive timely diagnosis, and merely 49% undergo recommended screening protocols, in comparison to a diagnosis rate of 35% and screening rate of 58% in NHW. Addressing this health disparity emphasizes the urgent need for targeted interventions to improve early screening and diagnosis within the Hispanic population. We hypothesize that genetic factors across different ethnicities/races may influence gene expression patterns during various stages, thereby contributing to CRC tumorigenesis and progression. To enhance the chances of identifying markers for early detection and diagnosis among Hispanics, we aim to identify new ethnicity-specific transcriptomic profiles. RNA sequencing of Hispanic CRC, NHW CRC and their respective normal tissues adjacent to the tumor (NAT), revealed unique sets of differentially expressed genes (DEGs) with a log2 foldchange of ≥ 2.0 and ≤ -2.0 and p-adjusted value ≤ 0.05 in Hispanic (1831) and NHW (1225) CRC populations compared to their respective NATs. Further analysis identified DEGs specific to early (1012) and late (765) stages of CRC within the Hispanic population, as compared to the respective stages in the NHW. Ingenuity Pathway Analysis (IPA) was used to uncover significant DEGs associated with the S100 family signaling pathway in Hispanic CRC samples. Previous studies have indicated the involvement of the S100 family proteins and their signaling pathways in CRC development, progression, metastasis, and drug resistance through interactions with WNT/β-catenin, RAGE, MAPK and NF-κβ signaling pathways. Our investigation of DEGs within the S100 signaling pathway and their interaction with downstream effectors suggests differential expression of genes crucial in cellular processes, including matrix metallopeptidases (MMP), mitogen-activated protein kinases (MAP2K) and Wingless-related integration site (WNT) family proteins. Exploring these proteins and their downstream effectors in Hispanic CRC tissues and organoids would elucidate specific functional attributes influencing CRC progression. Understanding the interaction of proteins identified in this study may serve as potential ethnicity-specific biomarkers or targets for the development of novel therapeutic interventions for early-stage CRC diagnosis in Hispanics. Citation Format: Soumya Nair, Brian I Grajeda, Sourav Roy. The role of the S100 family signaling pathway proteins in Hispanic colorectal cancer disparities [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C110.

Contributions to Colorectal Cancer Disparities

Contributions to Colorectal Cancer Disparities

The Revised United States Preventive Services Task Force Screening Recommendations and Racial/Ethnic Differences in Colorectal Cancer Screening in a Boston Healthcare System.

To evaluate the impact of the updated United States Preventive Services Task Force colorectal cancer (CRC) screening recommendations on screening rates in a large health system. We reviewed Massachusetts General Brigham electronic health record data for individuals eligible for CRC screening between January 3, 2020, and January 5, 2023, and calculated whether age-eligible individuals were up-to-date with CRC screening. There were large declines in the percentage of individuals who were up-to-date with CRC screening for all racial/ethnic groups, with non-Hispanic Asians being largest (-13.5%). Health systems should implement culturally tailored strategies to reach and screen newly eligible individuals for CRC screening to prevent worsening disparities in CRC.

Sustaining Improvements in Colorectal Cancer Across Delaware:: A Look at Racial Disparities a Decade Later.

A previously initiated statewide effort in Delaware improved outcomes in colorectal cancer (CRC) racial disparities. Objective. To examine whether improvements in racial disparities for CRC have been sustained a decade later and the status of Delaware's current cancer burden. Methods. Cancer incidence data from the Delaware Cancer Registry, mortality data from the Centers for Disease and Control and Prevention (CDC)'s National Center for Health Statistics, and cancer screening data from CDC's Behavioral Risk Factor Surveillance System were analyzed. Five-year age-adjusted incidence and mortality rates were calculated, and comparisons were made between non-Hispanic Black and non-Hispanic White groups using rate ratios. Distributions by cancer stage were compared between time periods by race/ethnicity utilizing chi-square statistical tests. The prevalence of Delawareans meeting recommendations for CRC screening was compared between time points for each race/ethnicity group using the Rao-Scott Modified chi-square test. Results. Comparing 2006-2010 and 2015-2019, CRC incidence rates decreased for non-Hispanic Black Delawareans from 51.0 to 39.6 per 100,000 population and decreased for non-Hispanic White Delawareans from 46.6 to 37.6 per 100,000 population. Between 2006-2010 and 2015-2019, CRC mortality rates decreased for non-Hispanic Black Delawareans from 16.8 to 15.1 per 100,000 population and decreased for non-Hispanic White Delawareans from 16.8 to 13.3 per 100,000 population. There were no significant differences in CRC incidence or mortality rates by race/ethnicity in either period. The distribution of cases by stage comparing 2006-2010 and 2015-2019 were not significantly different for either race/ethnicity group. There were no significant differences in meeting CRC screening recommendations comparing 2010 and 2018 by race/ethnicity or directly comparing race/ethnicity groups in either year. Conclusions. Delaware has sustained improvements in CRC incidence, mortality rates, and disparities between non-Hispanic Black and non-Hispanic White groups but will continue to monitor CRC trends and outcomes to ensure early diagnosis and that disparities are eliminated.

Geographical Disparities in Colorectal Cancer in Canada: A Review.

Colorectal cancer (CRC) is a prominent contributor to cancer-related mortality in Canada. This review paper sheds light on the research conducted in Canada to scrutinize the influence of economicfactors. The review seeks to uncover notable disparities in Colorectal cancer incidence and mortality rate across diverse Canadian populations, including Indigenous communities, rural dwellers, and individuals with lower socioeconomic status (SES). Recent investigations reveal significant disparities in CRC incidence, mortality, and treatment outcomes among various demographic groups in Canada. Indigenous peoples, rural populations, and those with lower SES are particularly vulnerable to these disparities. Access to screening and specialized cancer care is notably limited for these marginalized populations, exacerbating existing health inequities. Furthermore, emerging evidence underscores the potential influence of dietary factors on CRC risk, highlighting the importance of tailored prevention and treatment strategies. The findings underscore the urgent need for targeted interventions aimed at enhancing access to CRC screening and specialized cancer care for disadvantaged populations in Canada. By addressing these disparities, more individuals can undergo timely screening and receive early-stage diagnoses, thereby improving prognosis and ultimately saving lives. However, to effectively bridge these gaps, further research is imperative to elucidate the underlying mechanisms driving these disparities and to identify and implement effective interventions.

Biomarker Testing Disparities in Metastatic Colorectal Cancer

Among patients with metastatic colorectal cancer (mCRC), data are limited on disparate biomarker testing and its association with clinical outcomes on a national scale. To evaluate the socioeconomic and demographic inequities in microsatellite instability (MSI) and KRAS biomarker testing among patients with mCRC and to explore the association of testing with overall survival (OS). This cohort study, conducted between November 2022 and March 2024, included patients who were diagnosed with mCRC between January 1, 2010, and December 31, 2017. The study obtained data from the National Cancer Database, a hospital-based cancer registry in the US. Patients with mCRC and available information on biomarker testing were included. Patients were classified based on whether they completed or did not complete MSI or KRAS tests. Demographic and socioeconomic factors, such as age, race, ethnicity, educational level in area of residence, median household income, insurance type, area of residence, facility type, and facility location were evaluated. The main outcomes were MSI and KRAS testing between the date of diagnosis and the date of first-course therapy. Univariable and multivariable logistic regressions were used to identify the relevant factors in MSI and KRAS testing. The OS outcomes were also evaluated. Among the 41 061 patients included (22 362 males [54.5%]; mean [SD] age, 62.3 [10.1] years; 17.3% identified as Black individuals, 78.0% as White individuals, 4.7% as individuals of other race, with 6.5% Hispanic or 93.5% non-Hispanic ethnicity), 28.8% underwent KRAS testing and 43.7% received MSI testing. A significant proportion of patients had Medicare insurance (43.6%), received treatment at a comprehensive community cancer program (40.5%), and lived in an area with lower educational level (51.3%). Factors associated with a lower likelihood of MSI testing included age of 70 to 79 years (relative risk [RR], 0.70; 95% CI, 0.66-0.74; P < .001), treatment at a community cancer program (RR, 0.74; 95% CI, 0.70-0.79; P < .001), rural residency (RR, 0.80; 95% CI, 0.69-0.92; P < .001), lower educational level in area of residence (RR, 0.84; 95% CI, 0.79-0.89; P < .001), and treatment at East South Central facilities (RR, 0.67; 95% CI, 0.61-0.73; P < .001). Similar patterns were observed for KRAS testing. Survival analysis showed modest OS improvement in patients with MSI testing (hazard ratio, 0.93; 95% CI, 0.91-0.96; P < .001). The median (IQR) follow-up time for the survival analysis was 13.96 (3.71-29.34) months. This cohort study of patients with mCRC found that older age, community-setting treatment, lower educational level in area of residence, and treatment at East South Central facilities were associated with a reduced likelihood of MSI and KRAS testing. Highlighting the sociodemographic-based disparities in biomarker testing can inform the development of strategies that promote equity in cancer care and improve outcomes for underserved populations.

Disaggregating U.S. Asian and Pacific Islanders: Colorectal cancer

BackgroundColorectal cancer remains a public health concern as the 4th most common cancer in the US. Incidence and mortality have been observed to differ between races; however, Asian and Pacific Islander ethnicities are often documented in aggregate. Recognizing that these groups are heterogeneous, this study seeks to disaggregate Native Hawaiian from the broader “Asian/Pacific Islander” group and examine disparate outcomes in colorectal cancer. MethodsDe-identified data from the Hawaii Tumor Registry was queried to evaluate colorectal cancer in the state of Hawaii. Primary outcomes were cancer stage at diagnosis, first course of therapies received, and duration of survival from diagnosis. Chi-square analyses were performed for differences in categorical variables. Results7943 Hawaii residents were diagnosed with colorectal cancer in 2008–2018 with 1151 (14.5 %) patients identifying as Native Hawaiian. Native Hawaiians were less likely to present with localized cancer (36.7 % vs. 41.7 %; p = 0.002) and more likely to be diagnosed with distant stage cancer compared to non-Native Hawaiians (25.2 % vs. 17.67 %; p < 0.0001) and, among those with distant metastases, more likely to receive chemotherapy (68.3 % vs. 61.1 %; p = 0.029). No significant differences were observed between races on analysis of CRC-specific mortality. ConclusionSignificant differences exist between disaggregated Asian and Pacific Islander ethnic groups. Native Hawaiians are observed to present with more advanced cancer at the time of diagnosis in comparison to ethnicities. Disaggregating these groups reveals racial and ethnic disparities that may inform public health measures. SynopsisDisaggregating Asian and Native Hawaiian and Pacific Islander groups reveals disparities in colorectal cancer. Native Hawaiians presented with more advanced disease across all studied ethnic groups. No significant differences were observed in colorectal cancer specific mortality across groups.

Investigating racial, gender, and socioeconomic disparities in early-onset versus late-onset colorectal cancer: An analysis using the NIH All of Us database.

e15520 Background: Colorectal cancer (CRC) is a significant public health concern, with disparities based on race, gender, and socioeconomic status increasingly recognized. The incidence of early-onset CRC (EOCRC) is rising, highlighting the need for detailed examination of disparities in EOCRC compared to late-onset CRC (LOCRC). This study utilizes the NIH All of Us database to explore these disparities. Methods: We conducted a cross-sectional analysis of 266,520 participants from the NIH All of Us Registered Tier Dataset v7. CRC cases were identified based on at least two recorded diagnoses in electronic health records. Participants were categorized into EOCRC if diagnosed before age 50 and LOCRC if diagnosed at age 50 or above. We compared demographic and socioeconomic variables, including gender, race/ethnicity, income, education, and smoking status, between the groups, using questionnaire responses. Statistical analyses were performed using R. Results: The average age at diagnosis was 42.1 years for EOCRC patients and 63.7 years for LOCRC patients. The EOCRC group had a higher proportion of females (57.8%) compared to the LOCRC group (49.2%, p = 0.006). Whites constituted the majority in both categories, but Hispanics were significantly more represented in the EOCRC group (21.1%) compared to the LOCRC group (11.1%, p &lt; 0.001). Individuals with a higher income (more than $100,000 per year) were more prevalent in the EOCRC group (29.9%) than in the LOCRC group (17.7%, p &lt; 0.001). There was no significant difference in education levels between the two groups (p = 0.52). A history of smoking 100 or more cigarettes was less common in EOCRC patients (32.8%) than LOCRC patients (48.1%, p &lt; 0.001). Conclusions: This analysis highlights significant disparities in racial and gender representation as well as income level. Despite observed differences between the two groups, Hispanics, females, and higher income alone may not explain the only influencing factors as other cofounders, like insurance level, may have impacted the result. Cigarette exposure was more prevalent in the LOCRC group, which may represent a stronger environmental influence on CRC within this group. These findings highlight the need for further research to understand the underlying causes of these disparities and to develop targeted interventions. By addressing these disparities, we can move towards more equitable outcomes across all populations. [Table: see text]

AI virtual patient navigation to promote re-engagement of U.S. inner city patients nonadherent with colonoscopy appointments: A quality improvement initiative.

100 Background: Colorectal cancer disparities loom large for underserved communities of color in the US where barriers to screening uptake can contribute to late-stage diagnosis and poor outcomes. Despite active outreach by skilled patient navigators (PN) at a NYC cancer center serving an ethnically minoritized and disadvantaged population, 59% (1,925/3,276) of patients either cancelled or did not show for their colonoscopy appointments in 2022. While PN re-engagement efforts led to 410 (21%) completing colonoscopy, 1,500 patients did not undergo potentially life-saving colon cancer screening that year. With the advent of conversational Artificial Intelligence (AI)-driven applications within health care offering a potential extension to a stretched workforce, our cancer center examined the use of an AI-based virtual patient navigator, MyEleanor, as part of a colorectal cancer screening quality improvement (QI) project. Methods: This QI project employed MyEleanor between Apr-Dec 2023 to target re-engagement of 2,400 patients nonadherent with colonoscopy appointments in 2022-2023. In place of human PNs, MyEleanor (a) called patients to discuss rescheduling, (b) assessed barriers to uptake, c) offered live transfers to clinical staff to reschedule, and d) provided procedure prep reminder calls. Evaluable outcomes included: (a) engagement with MyEleanor via identity confirmation, (b) live transfers accepted (actionable), (c) colonoscopy completion rate, and (d) patient volume, with (d) barriers to care, and (e) predictors of actionable engagement examined. Results: Over 8 months, 57% (1,368/2,400) of patients engaged with MyEleanor, with 58% (789) of this group, or 33% overall, accepting the live transfer. The completion rate for patients who did not show for initial appointment nearly doubled from 10% to 19% from 2022 to 2023 (pre to post-MyEleanor). Overall patient volume increased by 36%. Patients who engaged were a Mean age of 56.66 (41-79 yrs), female (66%), Hispanic (41%), Black (33%), English (73%) or Spanish (25%) speaking, and partnered (37%). Nearly one third reported at least two barriers to screening; top barriers included lack of perceived need (19%), time (18%), and MD encouragement (16%), medical mistrust (14%), and concerns about findings (13%) and cost (12%). Greater number of barriers predicted actionable engagement, (F(1366) = 354, p &lt; 0.001), with Spanish-dominant patients and those declining to identify their race reporting nearly twice the number of barriers, F(1366) = 138.98 and F(1366) = 5.17, p &lt; 0.001, respectively). Conclusions: This project demonstrates high potential of an AI patient navigator in helping to overcome patient attrition that can lead to colon cancer disparities while improving patient volume. Next phase of the project will examine impact on patient prep adherence, staff burden, and revenue.

Addressing Colorectal Cancer Disparities in Unhoused Populations: A Call for Equitable Access and Compassionate Care

AbstractHousing is essential for health. Unhoused individuals have markedly worse health status than the general population culminating in higher rates of premature mortality. Cancer is a leading cause of death in older unhoused adults. Caring for unhoused patients at risk for or with colorectal cancer poses challenges at every stage of oncologic care: prevention, screening, diagnosis, treatment, and follow-up. These challenges result in later stages at diagnosis and worse overall survival. Health systems can work to advance health equity in colorectal cancer in unhoused patients by improving access to care, transitions of care, health care quality, and focusing on socioeconomic/environmental impact.

Difficulties and Disparities in Colorectal Cancer End-of-Life Care: A Patient's Story

AbstractPatients with advanced colorectal cancer nearing the end of life require a multidisciplinary approach to address the unique challenges they face. Using a case vignette, we outline the various stages of a patient's journey with advanced rectal cancer and the common obstacles to their care as they interface with the medical system. We highlight how Black persons might be vulnerable to differences in screening, treatment, procedural interventions, end-of-life care, and health care decision-making. The article also addresses how health inequities and barriers relating to concordant treatment goals can impact the relationship between patient and surgeon. This vignette illustrates the importance of ensuring a team approach to treatment and the value of early involvement of palliative medicine for patients with advanced colorectal cancer.

Abstract 6682: Bile acid profiles and racial disparities in colorectal cancer: Exploring the protective role of secondary bile acid derivatives

Abstract Background: Colorectal cancer (CRC) is the third leading cause of cancer death in the United States, with diet and gut microbiota-derived bile acids implicated as long-term risk factors. The interplay between bile acids and immune cell differentiation, particularly of macrophages and T-cells, is a crucial aspect of the CRC microenvironment. Given the high-animal-fat diets' influence on the microbiome’s production of hydrophobic secondary bile acids such as deoxycholic acid (DCA) and lithocholic acid (LCA), this study investigates the potential immunomodulatory effects of their lower concentrations and their isomers in possibly fostering M2-like macrophage expansion. Methods: Clinical samples were obtained during colonoscopies with no tumor findings at Rush University Medical Center, Chicago. RNA was extracted from colonoscopy biopsies for NanoString RNA expression analysis, while bile acids were isolated from both lyophilized stool and frozen serum samples. To explore the immunological effects of secondary bile acids, the macrophage RAW 264.7 cell line, alongside peritoneal macrophages and bone marrow-derived macrophages (BMDMs) from C57BL/6J mice, were treated with LCA and LCA isomers. Following the bile acid treatment, LPS (100 ng/mL) or IL-4 (40 ng/ml) was added to elicit pro-inflammatory or anti-inflammatory states, respectively. After 48 hours, conditioned media were collected for enzyme-linked immunosorbent assay (ELISA), while cells were analyzed by flow cytometry and rt-qPCR. Results: Contrary to initial hypotheses, the levels of DCA and LCA levels were not significantly different between African American and non-Hispanic White subjects. Notably, allo-isomers and oxo-derivatives of these bile acids, which may promote Treg and M2-like macrophage expansion, were substantially lower in African American subjects. Ex vivo treatments with isoalloLCA and IsoLCA led to notable changes in the M2 macrophage differentiation and shifts in PGE2 production upon exposure to inflammatory or anti-inflammatory stimuli, suggesting a nuanced alteration in the macrophage-mediated inflammatory response. Conclusion: This study highlights a significant ethnic variation in bile acid profiles, with a potential impact on immune modulation and CRC risk. The reduced presence of certain bile acid isomers in African American subjects may influence the risk of CRC through altered macrophage differentiation and function. These findings emphasize the need for personalized dietary and therapeutic strategies to modulate the bile acid metabolome, potentially reducing CRC disparities. Citation Format: Hanchu Dai, Patricia G. Wolf, Lisa Tussing-Humphreys, Ece Mutlu, Jason M. Ridlon, Rex Gaskins. Bile acid profiles and racial disparities in colorectal cancer: Exploring the protective role of secondary bile acid derivatives [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6682.

Abstract 6135: Racial and ethnic differences in site of de novo metastases in patients with colorectal cancer: A SEER analysis

Abstract Purpose: Disparities in colorectal cancer (CRC) mortality may be driven by differences in access to care, tumor biology, and propensity to spread to distant sites. We examine differences in patterns of de novo metastases by race/ethnicity and age. Methods: We identified 248,732 CRC patients listed in the Surveillance, Epidemiology, and End Results (SEER) database diagnosed with a first primary invasive CRC from 2010-2020, aged 20+ years at diagnosis, with complete data on SEER summary stage, and not diagnosed only by autopsy/death certificate. Outcomes included de novo metastatic site (no metastasis, liver, lung, brain, bone) and pattern (no metastasis, liver only, lung only, liver and lung, other). We used logistic regression to calculate odds ratios (OR) and 95% confidence intervals (95% CI) for the associations between 1) demographic and tumor characteristics (site, side, T stage, N stage) and site of de novo metastases , and 2) race/ethnicity and site of de novo metastases stratified by age (20-49, 50-74, 75+). We used multinomial logistic regression to assess the association between demographic and tumor characteristics and pattern of metastasis. Models adjusted for age, race/ethnicity, sex, site (colon, rectum), side (left, right), T stage, and N stage. Results: 62,844 stage IV CRC cases were diagnosed from 2010-2020, and liver was the most common metastatic site (72%). Relative to age 50-74, age 20-49 at diagnosis was more strongly associated with de novo liver metastases (OR: 1.07; 95% CI: 1.02-1.11) and less with lung (OR: 0.86; 95% CI: 0.80-0.92) or brain (OR: 0.69; 95% CI: 0.52-0.93) metastases. Relative to Non-Hispanic White (NHW) patients, Non-Hispanic American Indian/Alaskan Native (AI/AN) patients had a higher risk of lung metastases (OR: 1.33; 95% CI: 1.07-1.65), Non-Hispanic Asian/Pacific Islander (API) patients had lower risks of liver (OR: 0.87; 95% CI: 0.83-0.92) and brain (OR: 0.67; 95% CI: 0.48-0.95) metastases, and Non-Hispanic Black (NHB) patients had higher risks of liver (OR: 1.35; 95% CI: 1.29-1.41), lung (OR: 1.36; 95% CI: 1.27-1.45), and bone (OR: 1.23; 95% CI: 1.08-1.41) metastases. In age-stratified analyses, the risks for NHB patients persisted across groups, while lower risks for API patients were not observed in the 20-49 group. API patients aged 20-49 had a higher risk of de novo lung (OR: 1.31; 95% CI: 1.06-1.61) and bone (OR: 1.63; 95% CI: 1.13-2.37) metastases, and the increased risk of lung metastases for AI/AN patients was larger in magnitude (OR: 2.26; 95% CI: 1.39-3.68). Age 20-49 was more strongly associated with a liver-only pattern (OR: 1.14; 95% CI: 1.09-1.19) and with less common distant sites (OR: 1.33; 95% CI: 1.25-1.41). Conclusions: Racial/ethnic differences in de novo metastatic CRC patterns exist overall and across age groups. These findings are consistent with disparities in risk of stage IV CRC and can inform surveillance priorities in CRC survivors. Citation Format: Nicole C. Loroña, Mariana C. Stern, Stephanie L. Schmit, Jane C. Figueiredo. Racial and ethnic differences in site of de novo metastases in patients with colorectal cancer: A SEER analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6135.

Abstract 6134: The Latino Colorectal Cancer Consortium: A resource for colorectal cancer disparities research

Abstract Purpose: The Latino Colorectal Cancer Consortium (LC3) was established to fill a gap in representation of the diverse Hispanic/Latino/a/x community in cancer genomic research and to enhance understanding of determinants of disparities in the burden of colorectal cancer (CRC). Methods: The LC3 joins together three established studies with deeply-annotated clinical, epidemiologic, and biologic data available for a heterogenous group of Hispanic/Latino/a/x men and women diagnosed with primary colorectal adenocarcinoma: the Hispanic Colorectal Cancer Study (California), the Total Cancer Care Protocol at Moffitt Cancer Center (Florida), and the Puerto Rico Biobank (southern Puerto Rico). Each contributing study collected data on demographics, medical history, family history, and lifestyle factors. Vital status, cause of death, treatment, and clinical characteristics were obtained through medical chart abstraction and/or linkage to cancer registries. Blood, saliva, or normal colonic tissues were used to extract and genotype germline DNA for a subset of participants. Tumor tissues (snap frozen or formalin-fixed paraffin-embedded) were evaluated by pathologists for diagnosis, tissue content, tumor cellularity, necrosis, immune infiltration, and additional histopathologic characteristics. Results: The LC3 has assembled 2,041 participants across the three studies to date, with recruitment ongoing. Median age at diagnosis is 57 (range: 19-93), 54% of participants are male, and 63% are colon cancer cases (vs. rectal cancer). Participants were diagnosed between 1999 and 2022. The target is to generate comprehensive multi-omic data on 600 LC3 participants. To date, 243 have genome-wide germline genotyping, 323 have paired tumor/normal whole exome sequencing, and 257 have T cell receptor immunosequencing (immunoSEQ, Adaptive Biotechnologies). Further, 206 cases are represented on a set of tissue microarray blocks (target N=281). Bulk RNA-seq data are to be generated on 250 tumors. Conclusions: The LC3 fills an important gap in research infrastructure for the scientific community. Key strengths of this unique consortium are its ability to capture a diversity of Latino CRC patients with respect to nativity and cultural heritage and to represent the spectrum of stages from early to metastatic. Ultimately, research from the LC3 will inform development of equitable precision medicine approaches and predictive models to improve the health of the rapidly-growing, heterogeneous Hispanic/Latino/a population. Citation Format: Nicole C. Loroña, Marco Matejcic, Daniel Sobieski, Nathalie T. Nguyen, Hannah J. Hoehn, Diana B. Diaz, Kritika Shankar, Esther Jean-Baptiste, Domenico Coppola, Clifton Fulmer, Ozlen Saglam, Kun Jiang, Teresita Muñoz-Antonia, Idhaliz Flores, Edna Gordian, José A. Oliveras Torres, Seth I. Felder, Julian A. Sanchez, Jason Fleming, Erin M. Siegel, Douglas Cress, Mariana C. Stern, Jamie K. Teer, Stephanie L. Schmit, Jane C. Figueiredo. The Latino Colorectal Cancer Consortium: A resource for colorectal cancer disparities research [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6134.

Abstract 1298: Assessing the impact of Medicaid expansion on colorectal cancer preventative services utilization

Abstract Introduction: Colorectal cancer (CRC) is the second leading cause of cancer mortality. CRC screening rates have steadily risen and incidence rates around the nation have declined. To date, forty-one states have expanded Medicaid across the United States, with 9 states remaining that have not expanded. Although, access through insurance has increased, colorectal disparities in screening and mortality persist. Other studies have shown that screening guideline concordance can be inconsistent based on insurance type. Data suggests Medicaid enrollees are more likely to present advanced-stage cancers than those privately enrolled. The screening differences throughout the United States emphasize how complex colorectal cancer disparities are and how insurance may play a role. Aims: Our study aims to investigate the impact of Medicaid expansion on timely CRC screenings, specifically examining whether these effects differ by African Americans, Hispanics, and White Americans. Methods: Data was utilized from the Behavioral Risk Factor Surveillance System (BRFSS) to analyze timely CRC screening data of adults below 138% of the federal poverty level (FPL) of states with different Medicaid expansion statuses. Most recently available data was used in our analysis spanning the years 2014-2022 in all 50 states. States were stratified by dummy variables for Medicaid expansion and non-expansion status. Timely CRC screenings were determined by eligible respondent responses. Difference-in-difference analyses were used to study the effect of Medicaid expansion on timely CRC screenings in states with different Medicaid expansion statuses. Results: Our sample included 60.52% White Americans, 12.22% African Americans, and 16.41% Hispanics in both Medicaid expanded and non-expanded states. Sex and race had significant associations to Medicaid expansion status and timely CRC screenings, particularly when analyzing race for Hispanics and White Americans. Between 2014 and 2022, timely CRC screening for low-income adults in Medicaid expansion states was at 33.15% compared to 23.17% from non-expansion status states. Notably, adults aged 45-64 demonstrated the highest differences in timely CRC screenings for Medicaid-expanded states (12.26% and 18.98%) compared to non-expanded states (9.27% and 13.96%, respectively). Citation Format: Paulette Omeaku. Assessing the impact of Medicaid expansion on colorectal cancer preventative services utilization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1298.