Su1367 Impact of Pre-Existing Biliary Stents on Eus Staging in Patients With a Head of Pancreas Mass

Self-expanding metal stents (SEMS) are superior for pre-operative drainage of the common bile duct (CBD) and palliation of biliary obstruction secondary to a stricture in the head of pancreas (HOP). Their use has therefore increased over the last 5-6 years and plastic stents are now less commonly used. Endoscopic ultrasound (EUS) is commonly used to aid in staging. SEMS may impair staging performance as acoustic shadowing from the SEMS can reduce the view of the posterior aspect of the tumour and its relationship to local vessels. A previous study suggested that the presence of plastic biliary stents impaired staging performance utilising radial EUS, while another small study found that SEMS made no difference. The aim of this study is to assess whether SEMS impair the accuracy of linear EUS staging in distal biliary obstruction.