Secular trends of intrahepatic cholangiocarcinoma in a high endemic area: A population-based study.

backgroundIntrahepatic cholangiocarcinoma (ICC) is one of the most aggressive malignancies. However, because of its scarcity there are limited population-based data available for investigations into its epidemiologic characteristics. In Taiwan, we have a national cancer registry database that can be used to evaluate the secular trends of ICC.

aimTo evaluate secular trends of ICC according to age, sex, and risk factors in Taiwan.

methodsIn this population-based study, we used the national Taiwan Cancer Registry database. Age-standardized and relative percent changes in incidence rates were used to describe secular trends in incidence rates and sex ratios of ICC in Taiwan.

resultsThe age-standardized ICC incidence rate among males increased from 1.51 per 100000 in 1993-1997 to 4.07 per 100000 in 2013-2017 and among female from 1.73 per 100000 to 2.95 per 100000. The incidence in females tended to plateau after 2008-2012. For males, the ICC incidence increased as age increased. In the long-term incidence trend of ICC in females, the incidence of the four age groups (40-44, 45-49, 50-54 and 55-59 years) remained stable in different years; although, the incidence of the 60-64 group had a peak in 2003-2007, and the peak incidence of the 65-69 and 70-74 groups occurred in 2008-2012. Among males, beginning at the age of 65, there were increases in the incidence of ICC for the period of 2003-2017 as compared with females in the period of 2003-2017.

conclusionIncreased incidence of ICC occurred in Taiwan over the past two decades. The increased incidence has progressively shifted toward younger people for both males and females.