OP23 Asymptomatic inflammatory bowel disease diagnosed during the colorectal cancer population screening in Catalonia

Abstract Background Background: It has been postulated that early treatment of inflammatory bowel disease (IBD) is associated with a better long-term response. In Catalonia, the early detection program for colorectal cancer (EDPCRC) has been active since 2010, and was extended to the entire Catalan territory in 2015. The aim of this study is to describe the natural history of IBD asymptomatic diagnosed through the EDPCRC in Catalonia. Methods Methods: Observational, longitudinal and retrospective study of patients with IBD detected in the EDPCRC with a positive faecal immunological test in 21 centers in Catalonia between 2010 and 2019. Data was collected from the clinical histories. Results Results: 237 patients were identified; 35 patients had symptoms before endoscopy and were excluded from the study, finally 200 patients were diagnosed with asymptomatic IBD during the EDPCRC; 109 ulcerative colitis (54.5%), 63 Crohn's disease (31.5%) and 28 unclassifiable colitis (14%). 35.5% were women (n=71) with an average age of 60 years (range 49-79). Of the asymptomatic, 40.5% developed symptoms (n=81), being diarrhea the most frequent (n=45; 55.6%). The median time to first symptom was 368 days. Treatment was prescribed in 74.5% (n=149) of the patients. Mesalazine was the most frequently prescribed drug (n=130). The main reason for prescribing it was endoscopic activity (n=107), followed by the appearance of symptoms (n=39) and the biochemical activity (n=9). Only 19 patients (9.5%) required biological treatment (5 infliximab, 10 adalimumab, 2 vedolizumab and 2 ustekinumab). 4 patients (2%) required surgery. Conclusion Conclusion: Less than half of patients diagnosed with IBD at a preclinical stage develop symptoms after the first year of follow-up. Only 9.5% require biological treatment and 2% surgery. Three-quarters of patients are prescribed treatment; the most used was mesalazine.