The efficacy and safety of a duckbill‐type anti‐reflux metal stent as the initial metal stent for distal malignant biliary obstruction in unresectable pancreatic cancer

Abstract Background The usefulness of duckbill‐type anti‐reflux metal stent (DMS) in self‐expandable metal stent‐naïve pancreatic cancer (PC) patients has not been well‐studied. This study aimed to evaluate the efficacy and safety of DMS in such patients. Methods We analyzed consecutive patients with unresectable PC who received a covered metal stent (CMS) as the initial self‐expandable metal stent at our institution. Technical success, functional success, causes of recurrent biliary obstruction (RBO), time to RBO (TRBO), adverse events (AEs), and reintervention rates were compared between DMS and conventional CMS (c‐CMS). Results A total of 69 patients were included (DMS: 28, c‐CMS: 41). Technical success, functional success, and AEs were similar between groups. Tumor ingrowth was more common in the DMS group (18% vs. 0%, p = 0.009), while non‐occlusion cholangitis tended to be more common in the c‐CMS group (0% vs. 15%, p = 0.074). Median time to RBO was similar between groups (276 vs. 273 days, p = 0.915). The anti‐reflux valve of DMS was found torn in 56% of patients. Endoscopic reintervention was successful in all cases, despite failed stent removal in 88% of patients in the DMS group. Conclusions DMS was not associated with longer time to RBO compared to c‐CMS in self‐expandable metal stent‐naïve patients.