Safety of biliary drainage with 6‐mm metallic stent for preoperative obstructive jaundice in pancreatic cancer: PURPLE SIX STUDY

Background and Aim The 10‐mm self‐expandable metal stent (SEMS) is the standard for endoscopic transpapillary biliary drainage before pancreatic cancer surgery. However, the efficacy of stents thinner than 10 mm has not been adequately validated. Therefore, we aimed to evaluate the safety of a 6‐mm fully covered SEMS (FCSEMS) for distal malignant biliary obstruction (DMBO) during preoperative chemotherapy for pancreatic cancer. Methods This was a single‐arm, multicenter, prospective phase II study of endoscopic transpapillary initial biliary drainage for DMBO before pancreatic cancer surgery. The primary endpoint was stent‐related adverse events, and the key secondary endpoint was the non‐recurrent biliary obstruction (non‐RBO) rate during the observation period for both resectable (R) and borderline resectable (BR) pancreatic cancers. Results The study enrolled 33 patients, among whom 32 received the study treatment. There were 23 and 9 cases of R and BR pancreatic cancers, respectively. The technical and clinical success rates were 97.0% and 90.1%, respectively. The stent‐related adverse event rate was 3.1% (n = 1, acute pancreatitis) (95% confidential interval, 0.00–16.2), which met the criteria to be considered safe. The overall non‐RBO rate during the observation period (median 96 days) was 78.1% (82.6% and 66.7% for R and BR pancreatic cancer cases, respectively). Conclusions The 6‐mm FCSEMS is an extremely safe metallic stent with a low stent‐related adverse event rate of 3.1% for preoperative biliary drainage in pancreatic cancer. It is considered the optimal stent for preoperative biliary drainage in terms of the non‐RBO rate. UMIN Clinical Trial Registry (UMIN‐CTR 000041704).