The role of endoscopy in malignant hilar obstruction

Malignant hilar biliary obstruction (MHO) is a medical challenge as regards both forming a correct diagnosis and its adequate management, in terms of treatment alternatives and palliative options. Surgical resection is the only curative treatment for the underlying disease, but the majority of patients are not suitable candidates because of an unresectable tumor or poor performance status. Biliary drainage (BD) can be achieved through the percutaneous transhepatic route or endoscopically, and the choice depends on a host of factors, including biliary anatomy and comorbidity of the patient. Though there is no consensus, the endoscopic approach is usually preferred over the former. Endoscopy can aid in both diagnosis (collection of histological as well as cytological samples, direct visualization of suspected malignant pathology, or use of endoscopic ultrasound [EUS] for evaluation and locoregional staging), and in achieving internal BD. Advances in the development of various stents, accessories and, more recently, the use of EUS have in fact further expanded its application in MHO management. The choice of stents to be used (type, make, and number), palliation methods, deployment techniques and the use of local ablative strategy are still evolving and require more data. The complexity of management of MHO mandates that each patient should receive a "personalized approach", all the way from establishing a diagnosis until final treatment, with the help of a multidisciplinary team effort. Herein, we provide a comprehensive literature review of the current role of endoscopy for MHO, according to its applications in various clinical settings.