Burden and trajectories of biliary tract malignancies in Taiwan from 1998 to 2022.

Background: Biliary tract cancers, though relatively rare, exhibit wide variations in incidence rates across countries. We conducted a population-based cohort study to delineate the epidemiological trends over 25 years in Taiwan.

Methods: Age-standardized incidence and mortality rates of biliary tract cancers were obtained from the Taiwan Cancer Registry. These cancers were identified using the International Classification of Diseases for Oncology codes C23-C24, which include those originating in the gallbladder and extrahepatic bile ducts while excluding intrahepatic cholangiocarcinomas. The annual percent change (APC) was calculated using joinpoint regression models.

Results: Male patients experienced an increasing incidence from 1998 to 2009 (APC = 1.54%) and remained stable thereafter. In contrast, female patients had stable incidence rates from 1998 to 2009, followed by a decrease from 2009 to 2022 (APC = - 1.30%). Age-specific analyses showed that younger generations exhibited a decreasing trend, while the elderly had stable or increasing incidence rates. The proportion of patients receiving surgical treatment declined during the study period, while those undergoing chemotherapy and radiotherapy significantly increased. Mortality rates decreased after 2007.

Conclusion: Considerable gender disparities and cohort effects exist in the incidence trends of biliary tract cancers. In addition to surgery, chemotherapy with or without radiation therapy has become an important component of multimodal treatment.