Associations between the Gut Microbiota, Race, and Ethnicity of Patients with Colorectal Cancer: A Pilot and Feasibility Study

SIMPLE SUMMARY: The trillions of microorganisms found in the human gut have broad impacts on health and disease including altering the risk of colorectal cancer. Given the emerging evidence that both the microbiome and colorectal cancer differ between racial and ethnic groups, we sought to explore the relationship between the gut microbiome and cancer health disparities. We performed a pilot and feasibility study in which 30 colorectal cancer patients from different racial and ethnic backgrounds were recruited to provide a stool sample and to complete a dietary survey. The majority (18/30) of participants were successfully sampled, providing preliminary support for associations between their gut microbes according to racial and ethnic background. Overall, this study supports the feasibility of analyzing the links between gut microbes and colorectal cancer disparities, laying the groundwork for large follow-up studies. ABSTRACT: Background: Colorectal cancer (CRC) is more prevalent among some racial and ethnic minority and low socioeconomic status populations. Although the gut microbiota is a risk factor for CRC and varies with race and ethnicity, its role in CRC disparities remains poorly understood. Methods: We examined the feasibility of recruiting sociodemographically diverse CRC patients for a microbiome study involving a home stool collection. We also explored whether race and ethnicity were associated with gut microbiome composition. We recruited Black/African American, Hispanic/Latino, and non-Hispanic White patients who were receiving care for active CRC to complete a comprehensive dietary and lifestyle survey, self-collect a stool sample, and complete an exit interview. Gut microbial diversity and composition were analyzed using 16S rRNA gene sequencing. Results: 30 individuals consented (of 35 who were eligible and contacted) with 5 (17%) Black/African American, 11 (37%) Hispanic/Latino, and 14 (46%) non-Hispanic White. A total of 22 (73%) completed the dietary and lifestyle survey; 18 (63%) returned a stool sample. Even after controlling for socioeconomic, dietary, or treatment-related covariates, microbiome composition was associated with race and ethnicity. Fusobacteriota (a phylum associated with the development and progression of CRC) was significantly higher in the Black/African American group compared to others, and microbial diversity was higher in samples from non-Hispanic White individuals compared to Hispanic/Latino individuals. Conclusion: Our study shows that it is feasible to recruit and collect stool samples from diverse individuals with CRC and found significant associations in gut microbial structure with race and ethnicity.