Liver Transplant is Associated with a Reduced Risk of Colorectal Dysplasia in patients with IBD and concomitant PSC.

Background: Primary Sclerosing Cholangitis (PSC) affects up to 8% of patients with Inflammatory Bowel Diseases (IBD; Crohn's disease (CD), ulcerative colitis (UC) and is associated with an increased risk of colorectal neoplasia (CRN) which may be in part due to altered bile acid composition. About 40% of patients with PSC undergo liver transplantation.

Objective: To examine whether liver transplantation modifies risk of colorectal cancer in patients with PSC and IBD.

Methods: This was a multi-institution retrospective cohort study comparing colon dysplasia/cancer in patients with PSC-IBD who underwent a liver transplant to those with PSC-IBD without a liver transplant. Our primary outcome was the development of flat or visible colon cancer, low-grade, or high-grade dysplasia. Multivariable regression models adjusting for relevant confounders examined effect of liver transplant on cancer/dysplasia occurrence.

Results: Our study cohort consisted of 320 patients with PSC-IBD with a liver transplant compared to 659 PSC-IBD controls without a liver transplant. Most (80%) had ulcerative colitis. During follow-up, 239 patients (24%) developed colorectal neoplasia. On multi-variable analysis, adjusting for age, sex, study site, duration of disease and type of IBD, liver transplantation was associated with a lower risk of colon dysplasia or cancer (OR 0.66, 95% CI 0.47 - 0.93). The findings were unchanged on adjusting for number of surveillance exams, chromoendoscopy or presence of endoscopically active disease. Dysplasia was more common in patients who developed recurrent PSC after transplant.

Conclusions: Liver transplantation was associated with a reduced risk of colon cancer/dysplasia in patients with PSC-IBD in our cohort.