Can an alteration of the gut microbiome increase risk of gastrointestinal malignancies? Insights from the National Inpatient Sample.

841 Background: The gut microbiome is composed of trillions of microorganisms, inhabiting the lining of the gastrointestinal (GI) tract. The gut microbiome plays multiple roles in upholding human health including maintaining metabolism and regulating immune homeostasis. Dysregulation of the gut flora is known as gut dysbiosis. Studies have shown that gut dysbiosis is linked to the development of malignancies such as colorectal cancer. The purpose of this study is to assess the correlation between an altered gut flora and development of GI malignancies. Methods: The National Inpatient Sample was queried between 2016-2020 for all adult patients with altered gut flora, defined by history of gastrointestinal/bariatric surgeries, history of clostridium difficile infection, long-term antibiotic use, and inflammatory bowel disease. Rates of various cancers were compared between this cohort and all other patients utilizing chi-squared tests. Binary logistic regressions were utilized to calculate odds ratios of developing the various cancers, adjusted for age, sex, Charlson Comorbidity Index (CCI), and smoking status. Results: A total of 7,758,168 hospitalizations with altered gut flora were identified. Esophageal cancer (aOR 3.16, 95% CI 3.08 - 3.24) and colorectal cancer (aOR 3.15, 95% CI 3.11 - 3.18) were observed to have the highest odds of occurring in patients with altered gut flora. Gastric, hepatobiliary, pancreatic, and neuroendocrine cancers also all had significantly higher odds of occurring in patients with altered gut flora. Conclusions: Our study shows that conditions altering the gut flora are associated with increased odds of malignancies of the GI tract. This suggests that the gut microbiome may play an intricate role in regulation of tumor cell proliferation. Optimization of gut health and restoration of gut flora may prove beneficial to patients at high risk for malignancies of the GI tract. Altered Gut Flora (%) Intact Gut Flora (%) Adjusted Odds Ratio (CI) p-value Esophageal 0.4 0.1 3.16 (3.08 - 3.24) <.001 Gastric 0.3 0.1 1.67 (1.64-1.69) <.001 Colorectal 2.5 0.6 3.15 (3.11 - 3.18) <.001 Hepatobiliary 0.4 0.3 1.04 (1.02 - 1.07) <.001 Pancreatic 0.6 0.3 1.34 (1.31 - 1.37) <.001 Neuroendocrine 0.2 0.1 1.38 (1.33 - 1.44) <.001