Introduction: There are limited recent data on the characteristics of inflammatory bowel disease (IBD)-associated colorectal cancer (CRC) and the use of colonoscopy prior to CRC diagnosis among persons with IBD. We analyzed IBD-CRC characteristics, survival after IBD-CRC diagnosis and the use of colonoscopy prior to IBD-CRC diagnosis over time.
Methods: We identified individuals with and without IBD from the University of Manitoba IBD Epidemiology Database and CRC from linkage to the Manitoba Cancer Registry. We compared characteristics of IBD-CRC and sporadic-CRC using logistic regression and survival after CRC diagnosis using Cox regression analysis. We assessed rate and predictors of colonoscopy use 5 years to 6 months prior to IBD-CRC.
Results: 1,262 individuals with CRC were included (212 IBD-CRC). IBD was associated with an increased risk of death after CRC diagnosis in 2004-2011 (HR 1.89; 95% CI 1.25-2.88) but not in 2012-2017 (HR = 1.002; CI 0.50-2.03). In the 5 years to 6 months prior to IBD-CRC (1989-2018), 51% underwent colonoscopy, which was very similar to IBD without CRC and contrasted to 9% among sporadic CRCs. Exposure to colonoscopy pre IBD-CRC remained stable through the study period (1989-2002 OR = 1.25; CI 0.77-2.01; 2003-2011 OR = 1.21; CI 0.56-1.70; reference 2012-2018). Exposure to colonoscopy pre-IBD-CRC was not associated with improved post-CRC survival.
Conclusion: The risk of death following CRC diagnosis is not impacted by a diagnosis of IBD in recent years. There is a very high proportion of post colonoscopy CRC among IBD-CRC, which has not changed over the years and needs detailed root-cause analysis and interventions.