Secular Trends in the Incidence of Cholangiocarcinoma in the USA and the Impact of Misclassification

Abstract

Background and Aims It has been reported that the incidence of intrahepatic cholangiocarcinoma (ICC) has increased in the USA, while extrahepatic cholangiocarcinoma (ECC) has decreased or remained stable. However, neither the recent trends nor the effects of the misclassification of Klatskin tumors are known. Methods Using the Surveillance, Epidemiology, and End Results program databases, we calculated the average annual age-adjusted incidence rates (AA-IRs) of ICC and ECC in 4-year time periods (1992–1995, 1996–1999, 2000–2003, 2004–2007). These AA-IRs were calculated with misclassified as well as correctly classified Klatskin tumors. AA-IRs were also calculated based on age, sex, and race. Multivariable Poisson regression models were used to evaluate the secular trends of ICC and ECC. Results The AA-IR of ICC was 0.92 in 1992–1995 and 0.93 in 2004–2007, while the AA-IR of ECC increased from 0.70 in 1992–1995 to 0.95 in 2004–2007. There was no significant trend in AA-IR of ICC (p = 0.07), while there was a significant increase in ECC across the 4-year time periods (p < 0.001). Klatskin tumors comprised 6.7 % of CCs with approximately 90 and 45 % misclassified as ICC during 1992–2000 and 2001–2007, respectively. Adjusted Poisson models showed no significant differences in the temporal trend of ICC or ECC due to misclassification of Klatskin tumors. Conclusions The incidence of ICC has remained stable between 1992 and 2007 with only slight fluctuations, while the incidence of ECC has been increasing. Misclassification of Klatskin tumors does not appear to play a significant role in the trends of CCs.

Cholangiocarcinoma: Current Knowledge and New Developments

“…During the last three decades, age-adjusted incidence rates (AAIR) of iCCA increased in Western Europe, while the incidence of extrahepatic CCA followed a stable to decreasing trend 3,5,6. Interestingly, AAIR of extrahepatic CCA in the United States had significantly increased throughout the last four decades while iCCA incidence remained overall stable 4. Causes for the changing trends in incidence have not been identified.…”

Current biologics for treatment of biliary tract cancers

“…Though BTCs are traditionally more common in Asian countries, their incidence has been rising in Western countries in recent decades (3). Though it is a rare disease, the global incidence is rising.…”

“…Chronic inflammation and bile stasis in the biliary tract are thought to be major risk factors underlying the pathogenesis of these cancers. Specific risk factors include primary sclerosing cholangitis, liver fluke (Clonorchis, Opisthorchis) infection, hepatitis B and C infections, cholelithiasis or choledocholithiasis, cirrhosis, alcohol, smoking, and fatty liver disease (3,4).…”

Cholangiocarcinoma in Germany: Epidemiologic trends and impact of misclassification

“…Notably, since the introduction of ICD‐O‐3 in 2000, both C22.1 and C24.0 are possible localization codes for these tumours. This classification for pCCA is therefore prone to ambiguities, which led to strongly varying degrees of misclassification and impacted epidemiologic trends of iCCA and eCCA . However, the impact of misclassification in Germany is unclear to date.…”