Are Dominant Strictures in Primary Sclerosing Cholangitis a Risk Factor for Cholangiocarcinoma?

PURPOSE OF REVIEW Cholangiocarcinoma is a devastating, unpredictable complication of large duct primary sclerosing cholangitis (PSC), which occurs in 5-15% of patients. The aim of this review is to discuss whether dominant strictures (DS) occurring in the larger bile ducts in PSC are a risk factor for the development of cholangiocarcinoma. RECENT FINDINGS The development of DS is related to specific genetic polymorphisms affecting the innate immune system and the microbiome. In a recent study, the mean survival of PSC patients with DS was much worse (13.7 years) than for those without a DS (23 years). Survival difference was related to a 26% risk of cholangiocarcinoma, which developed only in those with DS. Half of the patients with cholangiocarcinoma presented within 4 months of the diagnosis of PSC. In another study, the risk of developing cholangiocarcinoma was directly related to the presence of underlying IBD, although this remains controversial. Efforts are being made towards surveying for cholangiocarcinoma including magnetic resonance imaging, endoscopic surveillance and serum tumour markers, but so far, an effective surveillance strategy has not been identified. DS should be treated endoscopically in the setting of symptoms, and there is limited evidence to suggest this may impact protectively on progression to cholangiocarcinoma. SUMMARY It is established that the presence of symptomatic DS occurring in the larger bile ducts in PSC can be the first presentation of cholangiocarcinoma. There is an increasing body of evidence that even when proven to be benign, dominant biliary strictures predispose to the future development of cholangiocarcinoma. Regular surveillance should be targeted at this selected high-risk group of PSC patients.