biliary obstruction, irrespective of a benign or a malignant cause. Compared with surgery, ERCP for palliative drainage of malignant biliary obstruction is less ...
EDITORIAL
Primary EUS-guided drainage for malignant distal biliary obstruction: not yet prime time! Endoscopic drainage has virtually replaced surgery for biliary obstruction, irrespective of a benign or a malignant cause. Compared with surgery, ERCP for palliative drainage of malignant biliary obstruction is less expensive, is associated with reduced morbidity, and provides a better quality of life.1-3 When compared with percutaneous transhepatic biliary drainage (PTBD), ERCP is associated with lower rates of adverse events and a better quality of life.4 Therefore, ERCP has been traditionally preferred over surgery and PTBD in cases with malignant biliary obstruction. Until recently, endoscopic drainage was synonymous with ERCP. However, not all cases are amenable to drainage with ERCP, the key reasons being inaccessible papilla as a result of altered anatomy or duodenal obstruction, and failure to cannulate the bile duct because of tumor infiltration of the papilla. In these cases, percutaneous drainage has been used for several decades. However, almost 1 in 5 patients undergoing PTBD has an adverse event such as occlusion, dislocation, cholangitis, or bile leakage.5 The advent of therapeutic EUS has contributed a potentially powerful addition to the available methods of endoscopic biliary drainage. EUS-guided biliary drainage (EUS-BD) has been shown to be safe and effective in multiple studies. In these studies, EUS has been used as a rescue procedure in patients with inaccessible papilla or failed ERCP. As a rescue therapy, EUS-BD has been found to be superior even to percutaneous drainage, with better clinical success, fewer adverse events, and lower need of reintervention.6,7 However, a majority of these studies were either retrospective or observational. In the current issue of Gastrointestinal Endoscopy, the study by Bang et al8 compares EUS and ERCP as a primary modality of biliary drainage in a randomized controlled setting. The authors randomized 67 patients with malignant biliary obstruction resulting from pancreatic cancer in either arm (ERCP, 34; EUS-BD, 33). An EUSguided transduodenal drainage technique was used in all the patients undergoing EUS-BD, and the use of a metal stent (8 mm 60 mm fully covered self-expandable metal stent) was similar in both groups.
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Given the low rate of adverse events with EUS-BD, the comparison is logical and ignites an important question: could EUS be used as a primary modality for biliary drainage in selected patients? The primary aim of the current study was comparison of adverse events between EUS and ERCP. The sample size was calculated on the basis of a 27% difference in adverse events (5% for ERCP vs 32% for EUS-BD). Interestingly, there was no significant difference in the incidence of adverse events in the 2 groups (EUS-BD 21.2% vs ERCP 14.7%), and the majority of the adverse events were mild to moderate. Because the adverse events
Dedicated devices or accessories for EUS-BD are still evolving. Moreover, the risk factors for adverse events and techniques to prevent them are yet to be mastered. from either procedure could vary according to centers on the basis of case volume and expertise, a larger sample size that could have detected a smaller difference in adverse events could have made the results of the study more clinically relevant. Furthermore, a cost-to-benefit comparison by the authors could also have made the results more applicable to real-world practice, where insurance does not always cover these procedures. EUS as a primary modality for drainage has been evaluated earlier, albeit not in a randomized manner.9-11 Nakai et al9 compared primary EUS-BD with rescue EUS-BD (after failed ERCP). Technical success (95% vs 93.8%) and adverse events (22.5% vs 18.8%) were similar in both groups.9 In another retrospective study, an EUS-guided rendezvous technique was compared with precut papillotomy for single-session biliary access.10 Technical success was higher in the EUS-BD group (98.3 vs 90.3%; P Z .03), and adverse events were similar in both groups (3.4% vs 6.9%). However, both studies were retrospective, with the inherent limitations. Hara et al12 prospectively analyzed the outcomes of primary EUS-BD using a prototype forwardviewing echoendoscope in 18 patients with distal biliary obstruction. The technical success rates were 94%, and early adverse events were encountered in 2 patients (11%). Even though the frequency of adverse events appears to be similar in both EUS-BD and ERCP in experienced hands, www.giejournal.org
Nabi et al
the nature of adverse events is different. Adverse events associated with EUS-BD predominantly include bleeding, bile leakage, pneumoperitoneum, stent migration, cholangitis, abdominal pain, and peritonitis,12 whereas pancreatitis is the most common adverse event associated with ERCP, followed by infections, bleeding, and perforations.13 The authors of this study reported a higher-thanexpected adverse event rate of 14.7% in the ERCP arm. The risk factors for post-ERCP pancreatitis (PEP) and the strategies to prevent them are well known and widely practiced. With the use of rectal nonsteroidal anti-inflammatory drugs, prophylactic pancreatic duct stents, and aggressive hydration, the incidence of PEP is reduced considerably. On the other hand, EUS-BD is a more recent procedure and is performed by highly skilled endoscopists at highvolume centers. Dedicated devices or accessories for EUS-BD are still evolving. Moreover, the risk factors for adverse events and techniques to prevent them are yet to be mastered. For the same reason, despite an increased technical success rate with EUS-BD (96.14% vs 90.68%, P < .001), the frequency of adverse events is not different between the studies published before and after 2013 (26.05% vs 22.36%, P Z .187).12 Furthermore, success may be lower and adverse events higher as the procedure is widely adopted and performed more frequently at low-volume centers. It is important to note that the present study evaluated transduodenal drainage, ie, EUS-choledochoduodenostomy. EUS-guided transhepatic drainage may be more challenging and associated with more adverse events than extrahepatic drainage. Therefore, the findings of this study should not be generalized at this time, especially when other techniques of EUS-BD such as EUS-HGS and EUS-rendezvous are also being practiced. In addition, EUS-BD was performed in a specific group of patients in this study: those who had pancreatic cancer with distal biliary obstructions. This could also have contributed to the limitation on the generalizability. Several questions still need to be addressed. (1) Is there a clinically relevant difference in efficacy between the 2 approaches? The present study was powered only to detect difference in adverse events; therefore, further randomized comparison with a larger patient population is required to determine any difference in efficacy. (2) What may be the possible “extended” indications for EUS-BD? EUS-BD is currently being used for patients in whom cannulation with ERCP has failed. However, the endoscopist may opt for EUS-BD at an earlier stage when the risks of continuing with standard cannulation techniques of ERCP are deemed higher than those of an alternative approach. Therefore, a potential indication could be cases with difficult cannulation defined by cannulation time (>10 minutes), number of cannulation attempts (>5), and injections into the pancreatic duct. www.giejournal.org
Editorial
However, it is important to remember that although EUS-BD is useful, it should not be a replacement for a good ERCP technique. Although advanced cannulation techniques such as precut sphincterotomy are not risk free and require considerable expertise, a timely precut sphincterotomy in expert hands increases the success rate and reduces PEP.14 In a large prospective study, cannulation was successful in 99.4% of patients, and EUS-BD was required in only 0.6%.15 In conclusion, we believe this is a much-needed study, the results of which would certainly contribute immensely to the evolving knowledge in the field of EUS-BD. However, is it prime time for EUS-BD as an alternative to ERCP for biliary drainage? Given the success rate and reasonable adverse event profile, EUS-BD has the potential to be a valuable alternative to ERCP. However, the technique needs to be standardized, and dedicated devices and accessories require further development. The best is yet to come for EUS-BD, and more evidence needs to be generated before we stretch our limits. DISCLOSURE All authors disclosed no financial relationships relevant to this publication. Zaheer Nabi, DNB Asian Institute of Gastroenterology Rupjyoti Talukdar, MD, FICP Asian Institute of Gastroenterology Asian Healthcare Foundation D. Nageshwar Reddy, MD, DM Asian Institute of Gastroenterology Hyderabad, India Abbreviations: EUS-BD, EUS-guided biliary drainage; PEP, post-ERCP pancreatitis; PTBD, percutaneous transhepatic biliary drainage.
REFERENCES 1. Perone JA, Riall TS, Olino K. Palliative care for pancreatic and periampullary cancer. Surg Clin North Am 2016;96:1415-30. 2. Maire F, Sauvanet A. Palliation of biliary and duodenal obstruction in patients with unresectable pancreatic cancer: endoscopy or surgery? J Visc Surg 2013;150:S27-31. 3. Artifon EL, Sakai P, Cunha JE, et al. Surgery or endoscopy for palliation of biliary obstruction due to metastatic pancreatic cancer. Am J Gastroenterol 2006;101:2031-7. 4. Inamdar S, Slattery E, Bhalla R, et al. Comparison of adverse events for endoscopic vs percutaneous biliary drainage in the treatment of malignant biliary tract obstruction in an inpatient national cohort. JAMA Oncol 2016;2:112-7. 5. Nennstiel WA, Frick G, Haller B, et al. Drainage-related complications in percutaneous transhepatic biliary drainage: an analysis over 10 years. J Clin Gastroenterol 2015;9:764-70. 6. Sharaiha RZ, Khan MA, Kamal F, et al. Efficacy and safety of EUS-guided biliary drainage in comparison with percutaneous biliary drainage
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when ERCP fails: a systematic review and meta-analysis. Gastrointest Endosc 2017;85:904-14. Lee TH, Choi JH, Park do H, et al. Similar efficacies of endoscopic ultrasound-guided transmural and percutaneous drainage for malignant distal biliary obstruction. Clin Gastroenterol Hepatol 2016;14: 1011-9.e3. 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. Nakai Y, Isayama H, Yamamoto N, et al. Indications for endoscopic ultrasonography (EUS)-guided biliary intervention: does EUS always come after failed endoscopic retrograde cholangiopancreatography? Dig Endosc 2017;29:218-25. Dhir V, Bhandari S, Bapat M, et al. Comparison of EUS-guided rendezvous and precut papillotomy techniques for biliary access (with videos). Gastrointest Endosc 2012;75:354-9.
11. Wang K, Zhu J, Xing L, et al. Assessment of efficacy and safety of EUSguided biliary drainage: a systematic review. Gastrointest Endosc 2016;83:1218-27. 12. Hara K, Yamao K, Hijioka S, et al. Prospective clinical study of endoscopic ultrasound-guided choledochoduodenostomy with direct metallic stent placement using a forward-viewing echoendoscope. Endoscopy 2013;45:392-6. 13. Andriulli A, Loperfido S, Napolitano G, et al. Incidence rates of postERCP complications: a systematic survey of prospective studies. Am J Gastroenterol 2007;102:1781-8. 14. Sundaralingam P, Masson P, Bourke MJ. Early precut sphincterotomy does not increase risk during endoscopic retrograde cholangiopancreatography in patients with difficult biliary access: a meta-analysis of randomized controlled trials. Clin Gastroenterol Hepatol 2015;13: 1722-9.e2. 15. Holt BA, Hawes R, Hasan M, et al. Biliary drainage: role of EUS guidance. Gastrointest Endosc 2016;83:160-5.
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