Mortality and cancer risk related to primary sclerosing cholangitis in a Swedish population-based cohort

Population-based studies on the epidemiology of primary sclerosing cholangitis (PSC) are sparse.

To investigate mortality and risk of cancer, and to identify risk factors for hepatobiliary cancer and the combined end-point liver related death or liver transplantation (OLT) in a population-based PSC cohort in Västra Götaland, Sweden.

Primary sclerosing cholangitis cases were identified in diagnostic registries. Case validation and follow up was provided through individual review of case files and linkage to the Swedish Cancer and Cause of Death registries. Standardized mortality ratio (SMR) and standardized incidence ratio (SIR) for cancer were calculated in relation to the background population. Cox's proportional hazards analysis was used to calculate crude and adjusted relative risks (RRs).

A total of 199 PSC patients were identified between 1992 and 2005. SMR in the PSC cohort was 4.20 (95% confidence interval (CI), 3.01-5.69). SIR for hepatobiliary cancer, cholangiocarcinoma and colorectal cancer were 177 (110-271), 868 (505-1390) and 2.87 (0.33-10.4) respectively. Age (RR=1.25 (1.01-1.53) per decade), female gender (RR=2.01 (1.09-3.72)), cholangitis (RR=2.56 (1.20-5.64)) and bilirubin (RR=3.95 (1.96-10.75) highest vs lowest quartile) were associated with the risk of liver related death or OLT. Age was associated with the risk of hepatobiliary cancer (RR 1.40 (1.01-1.95) per decade).

Primary sclerosing cholangitis was associated with a four-fold increase in mortality in this population-based study. In accordance with previous studies, the risk of hepatobiliary cancer was dramatically increased. However, the increased risk of colorectal cancer reported in previous studies could not be confirmed.