Introduction/Background: Colorectal cancer (CRC) has long been associated with inflammatory bowel disease (IBD), thought to be due to chronic mucosal inflammation. With newer IBD treatments, the incidence of CRC is decreasing, possibly due to improved therapies or improved treatment endpoints. Aims: Our primary aim was to assess for risk factors for CRC in IBD patients compared to IBD patients with adenomas to identify those at higher risk for CRC to target preventive measures. Methods: We performed a retrospective case-control study at a Veteran’s Affairs (VA) medical center. Data collection included IBD history, presence of active inflammation, history of prior adenomas, family history of CRC, labs, endoscopy and pathology results at the time of CRC or adenoma diagnosis (Table 1). The cases of CRC were then compared to a cohort of IBD patients with adenomas matched for age, IBD diagnosis, and gender. A matched-pair (1 case: 2 controls) conditional logistic regression model used backward, forward, and stepwise procedures for variable selection. Results: Only 17 IBD patients with CRC (8 UC, 9 CD) met criteria and were disease- and age-matched with 34 IBD patients with adenomas (16 UC, 18 CD) (Table 2). In the IBD cases, a higher hemoglobin was found to have an estimated odds ratio of 0.343 (95% CI 0.137 – 0885). This indicates that with one unit increase in hemoglobin, the odds of developing colon cancer is decreased by 65%. No other variables were significant. Conclusion: In this single-center, case-control, retrospective analysis, higher hemoglobin levels were associated with a lower risk of having CRC. This finding is likely due to mucosal healing or due to occult blood loss in those with CRC. Though larger studies are still needed, our results suggest no difference between IBD patients with CRC versus adenomas and stress the importance of regular CRC surveillance in IBD patients, particularly those with anemia.
