Advances of Peroral Cholangioscopy and EUS for Indeterminate Biliary Lesions

Abstract

Traditionally, biliary lesions have been considered to be indeterminate when a diagnosis cannot be made after basic laboratory work-up, abdominal imaging and endoscopic retrograde cholangiopancreatography (ERCP) with biliary sampling. Although ERCP is a first-line diagnostic modality for indeterminate biliary lesions, the diagnostic yield of ERCP-based tissue sampling is insufficient. In a recent, peroral cholangioscopy (POC)- guided forceps biopsy and endoscopic ultrasound-guided fine-needle aspiration (EUSFNA) are evolving as reliable diagnostic procedures for indeterminate biliary lesions. In previous studies, EUS-FNA was sensitive and highly specific for diagnosing malignancy in biliary strictures. However, EUS-FNA has several limitations as a routine clinical procedure for all biliary strictures. Newly developed POC systems, such as the SpyGlass direct visualization system and direct POC using an ultra-slim endoscope, have led to excessive improvements in technical performance and diagnostic yields for biliary strictures. However, the performance of POC-guided target biopsy for distal bile duct strictures is technically difficult, and this approach has a limited ability to diagnose biliary strictures caused by non-intraductal, extrinsic compressed malignancies, such as a pancreatic cancer. Therefore, a tailored approach using optimized endoscopic modalities that are specific to the characteristics of a given biliary stricture is needed to achieve a high diagnostic yield for indeterminate biliary lesions.