S2377 Gastrointestinal Cancer Incidence in Primary Sclerosing Cholangitis: Impact of Inflammatory Bowel Disease Status

Introduction: Primary sclerosing cholangitis (PSC) is a chronic liver disease associated with increased risk of gastrointestinal (GI) cancers, particularly cholangiocarcinoma and colorectal cancer. A large proportion of PSC patients also have inflammatory bowel disease (IBD). We aim to compare the incidence of GI malignancy in patients with PSC compared to those with PSC and IBD. Methods: We conducted a multicenter retrospective study on adult patients with PSC between January 2000 and May 2024. Collected data included demographics, medical history, and incidence of GI cancers. Primary outcome was the incidence and timing of GI cancer following PSC diagnosis. Fisher’s exact test was used. Results: Among 612 patients with PSC, 99 (16.2%) developed GI cancers following PSC diagnosis. Patients were categorized into 3 groups: PSC-only, PSC-first (PSC preceding IBD or both diagnoses within 3 months), and IBD-first (IBD diagnosed before PSC). The incidence of GI cancer was proportionally highest in the PSC-only group (18.1%), followed by IBD-first (16.9%) and PSC-first (11.8%). Across the entire cohort, cholangiocarcinoma was the most common malignancy (n = 72), followed by colorectal cancer (n = 19), gallbladder cancer (n = 6), and liver cancer (n = 5). Cholangiocarcinoma occurred in 12.8% of IBD-first, 12.6% of PSC-only, and 7.6% of PSC-first patients. Comparing PSC-only to those with IBD (IBD-first + PSC-first), there was no significant difference in GI cancer (P = 0.50) or cholangiocarcinoma (P = 0.76). No significant differences were seen between PSC-first and IBD-first groups for GI cancer (P = 0.194) or cholangiocarcinoma (P = 0.138). The mean age at GI cancer diagnosis was highest in the PSC-only group (56.8 ± 15.6 years), compared to 45.4 ± 12.0 in IBD-first and 43.6 ± 17.2 in PSC-first groups. Time from PSC diagnosis to GI cancer was longest in PSC-first (12.3 ± 11.9 years) while it was shortest in IBD-first group (6.0 ± 7.3 years). Conclusion: GI cancers occurred in nearly 1 in 6 PSC patients, with cholangiocarcinoma being most common, followed by colorectal and gallbladder cancers. PSC-only and IBD-first groups had similar GI cancer proportions, though IBD-first patients were younger at diagnosis and had a shorter interval from PSC to cancer. These findings suggest differences in cancer presentation by IBD status and support the need for individualized surveillance strategies in PSC.