Malignant biliary obstruction: endoscopic ultrasound-guided versus endoscopic retrograde cholangiopancreatography-guided biliary drainage

We read with interest the meta-analysis by Bishay et al. comparing endoscopic ultrasound-guided biliary drainage (EUS-BD) and endoscopic retrograde cholangiopancreatography (ERCP)-guided drainage in the primary treatment of malignant biliary obstruction [1]. The authors concluded that EUS-BD showed similar clinical success rates to ERCP. However, we have some questions as follows.

First, all included studies were for distal malignant biliary obstruction, but the title suggested comparison for all levels of obstruction (hilar and distal). A more accurate title would have been better.

Second, study selection was questionable. It was not clear whether biliary drainage was performed as the primary treatment in the Ridtitid et al. study [2]; this study should be excluded. Another study [3] was excluded because patients had indwelling duodenal stents; however, the inclusion/exclusion criteria did not preclude these cases from inclusion.

Third, “mixing apples and oranges” – definitions among studies were not congruent: clinical success was defined as a bilirubin decrease within 4 weeks by Kawakubo [4] and Park [5], within 2 weeks by Ridtitid [2] and Bang [6], and within 1 week by Paik [7]. For outcome procedure time, Paik used a “one-step” device that expedited the process of EUS-BD. Patients with surgically altered anatomy were included in the Paik study, but excluded in the Park and Bang studies. It is well known that surgically altered anatomy will render ERCP more difficult and prolong the procedure time. For adverse events, stent dysfunction was considered an adverse event by Paik, but not by Kawakubo and Park.

Finally, when extracting data from the Paik study, the authors incorrectly reported no stent occlusion in the EUS-BD group and three in the ERCP group; in fact, there were 8 and 23, respectively. In addition, the authors incorrectly reported no stent migration in the EUS-BD group, when in fact, there were two.

We think these issues might reduce the strength of the study outcomes and must be recognized.

• References

• 1 Bishay K, Boyne D, Yaghoobi M. et al. Endoscopic ultrasound-guided transmural approach versus ERCP-guided transpapillary approach for primary decompression of malignant biliary obstruction: a meta-analysis. Endoscopy 2019; 51 DOI: 10.1055/a-0901-7343.
• 2 Ridtitid W, Kongkam P, Angsuwatcharakorn P. et al. Ultimate outcomes of endoscopic transpapillary stenting (ETS) versus EUS-guided choledochoduodenostomy (EUS-CDS) using self-expandable metallic stent (SEMS) in patients with inoperable malignant distal biliary obstruction. J Gastroenterol Hepatol 2016; 31 (Suppl. 03) 272-273
• 3 Hamada T, Isayama H, Nakai Y. et al. Transmural biliary drainage can be an alternative to transpapillary drainage in patients with an indwelling duodenal stent. Dig Dis Sci 2014; 59: 1931-1938
• 4 Kawakubo K, Kawakami H, Kuwatani M. et al. Endoscopic ultrasound-guided choledochoduodenostomy vs. transpapillary stenting for distal biliary obstruction. Endoscopy 2016; 48: 164-169
• 5 Park JK, Woo YS, Noh DH. et al. Efficacy of EUS-guided and ERCP-guided biliary drainage for malignant biliary obstruction: prospective randomized controlled study. Gastrointest Endosc 2018; 88: 277-282
• 6 Bang JY, Navaneethan U, Hasan M. et al. Stent placement by EUS or ERCP for primary biliary decompression in pancreatic cancer: a randomized trial (with videos). Gastrointest Endosc 2018; 88: 9-17
• 7 Paik WH, Lee TH, Park DH. et al. EUS-guided biliary drainage versus ERCP for the primary palliation of malignant biliary obstruction: a multicenter randomized clinical trial. Am J Gastroenterol 2018; 113: 987-997