Summary

It is well accepted that patients with ulcerative colitis (UC) are at increased risk of developing colorectal carcinoma. Since 1992, several studies have examined the hypothesis that patients with concomitant primary sclerosing cholangitis (PSC) are at significantly increased risk of developing colorectal cancer or dysplasia. The size, design, end points, and populations involved in these studies have varied but critical review suggests that colorectal cancer is more common in the setting of PSC. Although the data do not allow exact quantification of the increased relative risk, there are nevertheless implications, both for understanding disease pathogenesis and for clinical practice.

An increased risk of developing colorectal carcinoma in patients with UC was first recognised in the 1920s.1 The magnitude of this risk varies in different studies with a range in cumulative risk after diagnosis in patients with pancolitis of between 1% and 3% at 10 years, 10% at 20 years, and 25% at 35 years.2-5It is now widely accepted that risk factors for malignant transformation are duration of disease and extent of colitis. The presence of graded dysplasia6 or DNA aneuploidy within the colorectal mucosa, and an early age at onset have been described as additional risk factors.4 It has also been suggested that pharmacological therapy of colitis with sulphasalazine or mesalazine may be associated with a reduced incidence of neoplastic transformation.7 ,8

PSC is a disease of unknown aetiology characterised by cholestasis associated with diffuse inflammation and fibrosis of the entire biliary tract.9 PSC has a variable clinical course, progressing eventually to cirrhosis and premature death from hepatic failure. Furthermore, PSC is accompanied by a risk of developing carcinoma of the bile ducts.10

Although PSC may occur in isolation, it is closely associated with inflammatory bowel disease, in particular UC. Up …