Malignant biliary obstruction (MBO) is usually caused by pancreatic tumours, cholangiocarcinoma, ampullary cancer, and metastatic cancer. Preoperative biliary decompression remains mandatory in cholangitis, need for neoadjuvant/induction chemotherapy, severe jaundice, severe pruritus and tumour preoperative work-up (1). Preoperative biliary drainage can be performed either endoscopically or percutaneously. Endoscopic methods include ERCP, and endoscopic ultrasound-guided biliary drainage (EUS-BD) (2).

Trans papillary stent placement with endoscopic retrograde cholangiopancreatography (ERCP) has been the preferred treatment modality for the treatment of malignant distal biliary obstruction (3). Major complications associated with the trans papillary route include the risk of post-ERCP pancreatitis and stent dysfunction secondary to tumour tissue ingrowth or overgrowth.

More recently, EUS-BD has emerged as an effective and alternate method for biliary drainage in cases of unsuccessful  ERCP. EUS-BD through the transluminal approach creates a biliary bypass with a stent through the duodenal bulb (choledochoduodenostomy) or stomach (hepaticogastrostomy). It permits accessing the biliary duct in patients with duodenal invasion or surgically-altered anatomy. It avoids ERCP-related complications, such as pancreatitis and post-sphincterotomy bleeding and does not involve traversing the biliary stricture, which decreases the risk of tumour ingrowth and reduces the probability of reintervention.

EUS-guided procedures have been conventionally restricted to inoperable patients, for fear of interference with eventual surgery. There are currently no guidelines for the optimal duration of preoperative biliary drainage (PBD). Delay due to PBD can lead to more advanced disease at the time of surgical resection and affect survival. In a randomised controlled study of 180 patients with pancreatic cancer, the mean time to surgery was 5.1 weeks in the PBD group and 1.2 weeks for patients who underwent early surgery (4). The biliary drainage duration of 4–6 weeks has been the goal before surgery (5,6).

In routine practice, time to surgery after PBD is affected by several factors including neoadjuvant therapy, cholangitis, and patient-related factors such as malnutrition and comorbidities.

To date, only a small volume of retrospective studies comparing EUS-BD with conventional ERCP exists and there is a lack a well-designed prospective study with robust data (7–9). The major limitations of trials are, small sample size, underpowered and single-centre studies, thus limiting the generalizability of the findings.