• hepatic malignancies
• extrahepatic malignancies
• primary sclerosing cholangitis

The paper of Bergquist and colleagues¹ is important for several reasons. In addition to confirming the increased risk of cholangiocarcinoma/hepatobiliary carcinoma in primary sclerosing cholangitis (PSC), they provide data on the size and nature of this risk. But more importantly, for the first time they demonstrate an increased risk of pancreatic cancer in addition to the well established risk of colonic malignancies in these patients. Thereby they demonstrate that PSC is a premalignant condition predisposing to several gastrointestinal cancers.

PSC patients are undoubtedly at an increased risk of developing cholangiocarcionoma. The size of this risk is however not universally agreed upon.² The present finding of 13% of hepatobiliary malignancies is based on the largest cohort of patients examined so far: as two thirds of all Swedish PSC patients were included, it is also probably the least selected series of patients. The high rate (74 %) of histological examination of livers post mortem and after transplantation among patients without hepatobiliary malignancy is an additional marker of the quality of this study. Although it is not clearly stated, one assumes that most of these are cholangiocarcinoma cases, indicating a standard incidence ratio of more than 100 for cholangiocarcinoma development among PSC patients and a frequency of cholangiocarcinoma development of 10–15%.

One remarkable finding of the present study is that a large proportion of PSC patients who developed hepatobiliary malignancy did so within the first year after diagnosis of PSC, indicating that the development of hepatobiliary malignancy in PSC may bring to light previously unrecognised PSC. This was even more evident in a joint European study.³

Not surprisingly, a 10-fold increased risk of colorectal cancers was also found. This is obviously linked to the high frequency of ulcerative colitis and Crohn's colitis in patients with PSC and implies that these patients should have colonoscopy at regular intervals both to have their colitis diagnosed (it may often be asymptomatic) and to look for colonic malignancies. Whether colonic malignancies were more often seen in PSC patients with colitis than in other colitis patients⁴ was not examined in the present study.

The new finding of a 14-fold increased risk of development of pancreatic cancer among PSC patients is particularly interesting. The possible diagnostic overlap between cholangiocarcinoma and pancreatic carcinoma has been underlined by the authors and confirmation of the finding should be attempted. Nevertheless, this finding may support the idea that PSC patients are at risk of developing several different types of gastrointestinal malignancies. As pancreatitis-like changes are sometimes seen in PSC,⁵ malignancy development in both the hepatobiliary system as well as in the colon-rectum and the pancreas could be secondary to chronic inflammation. One should also consider however that it may not be solely a predisposition to develop PSC that may be linked to specific genes but also the risk of developing gastrointestinal malignancy.⁶ The study of Bergquist et al should stimulate further studies on the mechanism of cancer development in PSC.