Background: Intrahepatic cholangiocarcinoma (IHCC) is the second most prevalent type of primary liver malignancy and has less than a 25% 5-year survival rate. Over the last two decades, the incidence of IHCC has been on the rise, however, the trends in mortality related to this form of malignancy are yet to be explored. Therefore, our study focuses on analyzing the trends and regional variations in IHCC-associated mortality among adults in the United States between 1999 and 2020.
Methods: Death certificates obtained from the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiological Research (CDC WONDER) database were assessed from 1999 to 2020 for any deaths associated with IHCC in adults >25 years of age. Age-adjusted mortality rate (AAMR) per 100,000 adults and annual percentage change (APC) stratified by age, year, gender, race, geographical regions, and place of death, were calculated using Joinpoint regression software.
Results: Between 1999 to 2020 a total of 113350 adults died from IHCC. The incidence of death increased from an AAMR of 1.5 in 1999 to 3.1 in 2020 with APC= 3.55 (95% CI 3.34 to 3.72. The rate of death increases with age and was seen to be highest in adults aged 85 years or above with an AAMR of 12.0 (APC 1.86[ 95% CI 1.47-2.26]). While considering genders, men were found to have significantly higher mortality when compared to women, as AAMR in men increased from 1.6 in 1999 to 3.5 in 2020 (APC 3.70 [95% CI 2.95 to 4.46]) and that in women rose from1.3 to 2.7between 1999 to 2020 (APC 3.55 [95% CI 3.34 to 3.77]). Among races, NH Asian and Pacific Islanders depicted an overall higher AAMR of 3.02. the trend depicted an upward slope from 2.3 in 1999 to 3.6 in 2020 (APC=1.96 [95% 1.43 to 2.49]). Moreover, AAMR varied substantially with geographical region, and with an AAMR of 2.6 it was concluded that the Northeast has the highest mortality rate. The trends showed an increment from 1.6 in 1999 to 3.5 in 2020 (APC 3.7 [95% CI 3.46 to 3.93]). Further consideration highlighted those metropolitan areas had higher mortality with AAMR of 3.65 (APC=3.65 [95% CI 3.49 to 3.80]) than non-metropolitan areas with AAMR 3.45 (APC= 3.45 [95% CI 3.16 to 3.74]). Among the Northeast census region, New England showed the highest IHCC-related mortality with an AAMR of 2.77, the rate increased gradually from 1.7 in 1999 to 3.8 in 2020 (APC=4.48 [95% CI 3.96 to5.00]).
Conclusions: IHCC-related mortality in US adults aged>25 years has increased between 1999 to 2020. The highest AAMR was observed in adults above 85 years of age, men, NH Asian and Pacific Islanders, Northeast region, and metropolitan areas. This raises a need for early diagnosis and targeted therapies to counter the rising trends.
