Inflammatory Bowel Disease Uncovered in Fecal Immunochemical Test Positive Patients in a Canadian Provincial Colon Cancer Screening Program

Abstract Objectives: Inflammatory Bowel Disease (IBD), comprising Crohn’s disease (CD) and ulcerative colitis (UC), is a chronic inflammatory condition that usually affects younger adults but has a second incidence peak in the older population. Most patients are diagnosed at colonoscopy to investigate symptoms but some are asymptomatic and discovered while participating in a colon screening program. We aimed to identify the incidence and outcome of subclinical IBD in Fecal Immunochemical Test (FIT) positive patients in the British Columbia Colon Screening Program (BCCSP). Methods: We conducted a retrospective chart review of patients who had colonoscopies for a positive FIT and were found to have colitis based on endoscopic and confirmed on histological assessment. Patient demographic, disease severity, and management data was collected. Results: Of 93,994 patients who were FIT positive and underwent screening colonoscopy between 2009 and 2017, 608 (0.6%) were found to have colitis. Data was extracted from 11 sites where 208 patients had colitis, and 191 of those met the inclusion criteria. 58 patients (30.4%) were diagnosed with UC, 109 patients (57.1%) with CD, and 24 (12.6%) with IBD unclassified (IBDU). Patients with CD and IBDU had higher terminal ileal intubation rates. 124 patients (64.9%) received treatment, of which 34 (17.8%) patients received biologics and 4 (2.1%) required surgery. Conclusion: Our study demonstrated a significant overall incidence of subclinical IBD. The predominance of CD in this population was a novel finding in our study, which is the largest of its kind in North America. Further research is needed to guide management of initially asymptomatic older patients with varying rates of IBD progression diagnosed during screening colonoscopies.