Preventable predictive factors of post-colonoscopy colorectal cancer in inflammatory bowel disease.

Background &aim: Post-colonoscopy colorectal cancer (PCCRC) is a colorectal cancer (CRC) diagnosed after a colonoscopy in which no cancer is detected (index colonoscopy). Although the overall cumulative rates of PCCRC are low in both the general population and inflammatory bowel disease (IBD) patients, the overall incidence of PCCRC in IBD is greater than that documented in the general population. This study aimed to identify the index colonoscopy-related factors and patients' characteristics influencing IBD-associated PCCRC development.

Materials and methods: We carried out an observational, retrospective study in which IBD-associated PCCRCs were diagnosed between 2010 and 2023. The PCCRC group was compared to a control cohort of IBD patients without CRC matched 1:1 by several demographic and clinical features as well as characteristics of index colonoscopy to minimize selection bias.

Results: Among 61 CRCs identified, 37 (61%) were PCCRC. Twelve of 37 (32%) PCCRC were diagnosed within 12 months after the previous negative colonoscopy, 15 (41%) within 12-36 months, and 10 (27%) within 36-60 months. In the multivariate analysis, the inadequate bowel preparation of the index colonoscopy (OR: 5.9; 95% CI: 11.1- 31.4) and the presence of high-risk factors for CRC (OR: 24.03; 95% CI: 3.1-187.8) were independently associated with PCCRC. Conversely, prior exposure to immunosuppressors/biologics (OR: 0.17; 95% CI: 0.03-0.83) and random biopsies sampling at index colonoscopy (OR:0.19; 95% CI: 0.04-0.85) were inversely associated with PCCRC.

Conclusions: More than 50% of CRCs in our population were PCCRC. PCCRCs were associated with previous inadequate cleansing and occurred more frequently in high-risk patients.