The colon and PSC: new liver, new danger?

See article on page 639 The close relation between primary sclerosing cholangitis (PSC) and inflammatory bowel disease (IBD) continues to provide more questions than answers. The prevalence of IBD in patients with PSC is about 55–75%, and PSC occurs in patients with ulcerative colitis at a frequency of 2.5–7.5%.1 2 PSC is found less often in Crohn’s disease where it is usually associated with colonic involvement. Recent studies have found an increased prevalence of colonic dysplasia and cancer in patients with PSC and ulcerative colitis compared with ulcerative colitis alone.3 4 The mechanism by which PSC increases the risk of colonic neoplasia is unknown. The increased long term survival of patients with both PSC and ulcerative colitis after liver transplantation may therefore put these patients at an increased risk of developing colorectal cancer in view of the increased neoplastic potential as a result of the immunosuppressive therapy required after liver transplantation. Indeed, some studies have suggested that there may be a higher incidence of colorectal cancer in the first two years after liver transplantation.5-7 This may reflect the higher doses of immunosuppression …