Endoscopic Inflammatory Patterns in Inflammatory Bowel Disease Patients with and without Primary Sclerosing Cholangitis Prior to Colorectal Cancer: A Retrospective Cohort Study

Aims Inflammatory bowel diseases (IBD) and primary sclerosing cholangitis (PSC) are associated with an elevated risk of colorectal cancer (CRC). While increased colonic inflammation is a recognized risk factor for CRC in IBD patients, the impact of concomitant PSC is not fully understood. This study aimed to compare pre-CRC endoscopic findings in IBD patients with and without PSC.

Methods We conducted a retrospective study of IBD patients who underwent colonoscopy one year prior to their CRC diagnosis. Data collected included demographics, PSC status, IBD duration, and CRC location, with CRC sites classified as right-sided (cecum, ascending colon, transverse colon) or left-sided (descending colon, sigmoid colon, rectum). Colonoscopy and pathology reports were reviewed to assign endoscopic scores [no inflammation (0), mild (1), moderate (2), severe (3)] and histologic scores [normal (0), quiescent (1), mild (2), moderate (3), severe (4)] by colonic laterality (right vs. left). Inflammation severity was qualitatively classified: endoscopic inflammation was categorized as normal/mild (≤ 1) or moderate/severe (> 1), and histologic inflammation as quiescent/mild (≤ 2) or moderate/severe (> 2). Statistical analyses included Student’s t-test for continuous variables and the chi-squared test for categorical data.

Results A total of 119 IBD patients met the inclusion criteria, of whom 50 had PSC. The most common CRC site in PSC-IBD was ascending colon (32%) vs rectum (33%) in non-PSC. PSC-IBD patients were diagnosed with IBD at a younger age (32±13 years vs 40±18 years; p=0.01) and developed CRC earlier (52±13 years vs 62±16 years; p=0.001). The duration of IBD prior to CRC diagnosis was not significantly different between groups.

Right- and left-sided CRCs. One year prior to CRC diagnosis, PSC-IBD patients had lower pancolonic (0.7±0.8 vs 1.5±1.2; p=0.04) and left colon endoscopic scores (0.7±0.8 vs 1.5±1.2; p=0.03) than non-PSC. Left colon moderate/severe endoscopic inflammation was more common in non-PSC patients (49% vs 11%; p=0.02).

Right-sided CRCs only. Pancolonic (0.8±0.8 vs 1.7±1.3; p=0.04) and left colon (0.8±0.9 vs 1.7±1.2; p=0.04) endoscopic scores were lower in PSC-IBD. Right colon endoscopic scores were non significantly different between PSC-IBD and non-PSC. Left colon moderate/severe inflammation was more common in non-PSC (57% vs 13%; p=0.02). There was no difference in right colon moderate/severe endoscopic inflammation between PSC-IBD and non-PSC.

Conclusions Endoscopic findings one year prior to CRC diagnosis indicate that PSC-IBD patients have lower inflammation scores compared to non-PSC patients. Although right-sided CRCs are more common in PSC-IBD patients, there was no significant difference in right colon inflammation scores. In contrast, non-PSC patients had higher inflammation in the left colon, aligning with their higher prevalence of left-sided CRCs.

Publication History

Article published online:
27 March 2025