IBD-associated CRC epidemiology and outcomes: an English population-based study

Introduction: People with inflammatory bowel diseases (IBD) of the colon are at an increased risk of colorectal cancer (CRC). This study investigates the epidemiology of IBD-CRC and its outcomes. Methods: Using population data from the English National Health Service (NHS) held in the CORECT-R data repository, all colorectal cancers with and without a prior diagnosis of IBD (Crohn’s, ulcerative colitis, IBD unclassified (IBD-U) and IBD with cholangitis) between 2005 and 2018 were identified. Descriptive analyses and logistic regression models were used to compare the characteristics of the two groups, and their outcomes up to 2 years. Results: 390,614 patients diagnosed with CRC were included, of whom 5,141 (1.3%) also had a previous diagnosis of IBD. IBD-CRC cases were younger (median age at CRC diagnosis (IQR) 66 (54-76) versus 72 (63-79) years (p<0.01)), more likely to be diagnosed with CRC as an emergency (25.1% versus 16.7% (p<0.01)) and have a right-sided colonic tumour (37.4% versus 31.5% (p<0.01)). A total colectomy was performed in 36.3% of those with IBD (15.4% of Crohn’s, 44.1% of ulcerative colitis, 44.5% of IBD-U and 67.7% of IBD with cholangitis). Synchronous (3.2% versus 1.6% p<0.01) & metachronous tumours (1.7% versus 0.9% p