Clinical observations suggest a recent increase in intrahepatic biliary tract malignancies. Thus, our aim was to determine recent trends in the epidemiology of intrahepatic cholangiocarcinoma in the United States. Reported data from the Surveillance, Epidemiology, and End Results (SEER) program and the United States Vital Statistics databases were analyzed to determine the incidence, mortality, and survival rates of primary intrahepatic cholangiocarcinoma. Between 1973 and 1997, the incidence and mortality rates from intrahepatic cholangiocarcinoma markedly increased, with an estimated annual percent change (EAPC) of 9.11% (95% CI, 7.46 to 10.78) and 9.44% (95%, CI 8.46 to 10.41), respectively. The age-adjusted mortality rate per 100,000 persons for whites increased from 0.14 for the period 1975-1979 to 0.65 for the period 1993-1997, and that for blacks increased from 0.15 to 0.58 over the same period. The increase in mortality was similar across all age groups above age 45. The relative 1-and 2-year survival rates following diagnosis from 1989 to 1996 were 24.5% and 12.8%, respectively. In conclusion, there has been a marked increase in the incidence and mortality from intrahepatic cholangiocarcinoma in the United States in recent years. This tumor continues to be associated with a poor prognosis. (HEPATOLOGY 2001;33:1353-1357.)
Intrahepatic cholangiocarcinomas are malignant tumors arising from the epithelial lining of the intrahepatic biliary tract. These tumors are challenging to manage, because they are associated with a poor prognosis and respond poorly to current therapies. 1 The etiology and pathogenesis of intrahepatic biliary tract malignancies remain poorly understood. Improved knowledge and understanding of the basic biology of these tumors may enhance our ability to diagnose, treat, or prevent these malignancies.
Epidemiologic studies have provided clues to the role of environmental factors in the etiology and pathogenesis of cholangiocarcinoma. Although these tumors are uncommon in the West, there is a striking global geographic distribution, with high disease prevalence in parts of Southeast and eastern Asia. 2 This geographic distribution has resulted in the identification of chronic biliary tract infestation with parasitic liver flukes, Opisthorchis viverrini and Clonorchis sinensis, as causative factors for cholangiocarcinoma. Although study of time trends in the incidence of cholangiocarcinoma may also help to identify specific etiologic factors, there have not been any published studies analyzing epidemiologic trends of this malignancy in the United States.
Recent reports have suggested an increase in mortality from primary liver cancers, including intrahepatic cholangiocarcinoma, in Japan and the United Kingdom. 3,4 The reasons for these changes remain unknown. Analysis of epidemiologic trends in disease frequency in areas of low endemicity may provide clues to potential etiologic factors. Thus, our aims were to determine incidence, mortality, and survival rates of primary intrahepatic cholangiocarcinoma in the United States.