Biliary strictures can arise from various entities ranging from benign to malignant conditions. In the absence of extrinsic compression, accurate characterization of strictures can be challenging and is crucial for patient prognosis and management. In case of suspected cholangiocarcinoma (CCA), improvement of confirmation and accurate local tumour staging is needed for therapeutic decisions. Cross-sectional imaging provides important information that is used for further planning of the diagnostic approach. Diagnostic ERCP has been widely replaced by MRCP but can be indicated for tissue acquisition (Tx). Transpapillary biopsy and/or brushing are easy to perform but are limited by a sensitivity of less than 60 %. EUS-guided Tx is considered as an additional diagnostic approach especially for distal or unresectable extrinsic biliary lesions. Seeding of tumour cells remains a potential concern. Single-operator cholangioscopy (SOC) provides direct visualization of the bile duct. It allows targeted Tx and enables interventions e.g. cannulation of difficult strictures. SOC appears to be a logical next step to increase diagnostic accuracy in indeterminate biliary strictures (IDBS). A meta-analysis reported a sensitivity of 74 % and specificity of 98 % for evaluation of malignant biliary strictures. Our group conducted a multicenter randomized controlled trial that demonstrated a significantly higher sensitivity for SOC compared to ERCP alone in terms of visual diagnosis. In addition, Tx under direct visual control was superior to ERCP guided brush cytology. Model analyses based on clinical data, and resource consumption suggest that initial SOC offers advantages over ERCP in decreasing the number of procedures and costs. In case of presumed diagnosis of CCA or IPMN, SOC allows accurate determination of intraductal extension and detection of skipping lesions which may change the surgical plan for surgical resection. Further progress of SOC can be expected from implementation of artificial intelligence for characterization of lesions and from larger instrument working channels facilitating Tx.
In conclusion, an invasive diagnostic approach is only justified for IDBS if results have a therapeutic impact. Indications should be made in a team for management of hepatobiliopancreatic diseases. Tx is frequently indicated for therapeutic decisions. SOC is complementary to ERCP, safe, effective, and technically easy. It is more accurate than ERCP for Tx and histological diagnosis. In addition, it allows targeted cannulation of difficult strictures and intraductal tumor mapping. SOC seems to be cost-effective depending on endoscopic expertise and consequences of false results of standard techniques. |
