Recent Advancement in Diagnosis of Biliary Tract Cancer through Pathological and Molecular Classifications

Abstract

Simple Summary The development of various molecular techniques has led to the introduction of a new classification for biliary tract cancer and a better understanding of the clinicopathological features of the disease. Furthermore, as new diagnostic modalities and research findings have been published, they enable accurate diagnoses, differentiations, and clinical assessments based on the characteristics of each subtype. This article reviews the current imaging and histologic diagnostic techniques along with future perspectives on molecular diagnosis, to approach precision medicine for biliary tract cancer.Abstract Biliary tract cancers (BTCs), including intrahepatic, perihilar, and distal cholangiocarcinomas, as well as gallbladder cancer, are a diverse group of cancers that exhibit unique molecular characteristics in each of their anatomic and pathological subtypes. The pathological classification of BTCs compromises distinct growth patterns, including mass forming, periductal infiltrating, and intraductal growing types, which can be identified through gross examination. The small-duct and large-duct types of intrahepatic cholangiocarcinoma have been recently introduced into the WHO classification. The presentation of typical clinical symptoms, as well as the extensive utilization of radiological, endoscopic, and molecular diagnostic methods, is thoroughly detailed in the description. To overcome the limitations of traditional tissue acquisition methods, new diagnostic modalities are being explored. The treatment landscape is also rapidly evolving owing to the emergence of distinct subgroups with unique molecular alterations and corresponding targeted therapies. Furthermore, we emphasize the crucial aspects of diagnosing BTC in practical clinical settings.