Endoscopic view of biliary ducts merging, representing EUS and ERCP convergence.

EUS vs. ERCP for Biliary Obstruction: Which Method Comes Out on Top?

Nico Varela in Health & Wellness December 2025 • 4 min read.

"Navigating the complexities of malignant biliary obstruction: An analysis of safety, efficacy, and optimal timing between EUS and ERCP."

Malignant biliary obstruction, a condition where the bile ducts are blocked due to cancer, poses significant challenges for gastroenterologists. Traditionally, endoscopic retrograde cholangiopancreatography (ERCP) has been a primary method to relieve this obstruction. However, endoscopic ultrasound-guided biliary drainage (EUS-BD) has emerged as a promising alternative. The core question is: Which approach provides the best balance of safety and efficacy for patients?

A prospective randomized controlled study by Park et al. published in 'Gastrointestinal Endoscopy', directly compared EUS-BD and ERCP-BD, concluding their safety profiles are similar. This study ignited interest and debate, particularly concerning sample sizes, methodologies for assessing stent patency, and causes of stent dysfunction. These factors significantly influence the outcomes and, ultimately, the choice between EUS and ERCP.

Adding another layer to the discussion, the timing of ERCP relative to cholecystectomy (CCY) has been examined. A study by Suarez et al. highlights trends and outcomes associated with different timings of these procedures. Optimizing this timing could reduce hospital stays and improve patient outcomes, thus underscoring the importance of carefully planned interventions.

EUS-BD vs. ERCP-BD: Diving Deeper into the Debate

Endoscopic view of biliary ducts merging, representing EUS and ERCP convergence.

The study by Park et al. aimed to demonstrate that EUS-BD is as safe as ERCP-BD for managing distal malignant biliary obstruction. While the study's conclusion suggests similar safety profiles, some experts have raised concerns about the sample size. According to Kazumichi Kawakubo, MD, PhD, and colleagues, the sample size might have been underpowered to detect clinically significant differences in stent patency between the two groups.

The critique centers on how stent patency was evaluated. Rather than treating stent patency as a continuous variable, it should have been assessed using Kaplan-Meier method or Cox proportional hazard model. These methods are designed to analyze time-to-event data, providing a more accurate representation of stent performance over time. By using these methods, a noninferiority test would require at least 150 patients in each group to reliably exclude any significant difference in stent patency.

Sample Size Concerns: The original study might not have included enough patients to detect meaningful differences.
Statistical Methods: Kaplan-Meier or Cox models are recommended for more accurate assessment of stent patency.
Impact of Stent Type: Covered SEMSs, designed to prevent tumor ingrowth, were used, but stent dysfunction still occurred due to ingrowth in the ERCP-BD group.

Another critical aspect is the cause of stent dysfunction in the ERCP-BD group. All cases of dysfunction were attributed to tumor ingrowth despite the use of covered self-expandable metal stents (SEMSs), designed to prevent this issue. This raises questions about the effectiveness of these stents in preventing tumor ingrowth and whether it underestimated the true efficacy of ERCP-BD. EUS-BD remains a viable alternative, but further randomized trials are needed to confirm its safety and efficacy compared to ERCP-BD.

Optimizing the Timing of ERCP and Cholecystectomy

In addition to the debate between EUS and ERCP, the timing of ERCP relative to cholecystectomy (CCY) is crucial for patient outcomes. A study by Suarez et al. highlighted the trends and impacts of timing these procedures, pointing out that the interval between ERCP and CCY can significantly affect hospital stays and patient well-being. Optimizing this timing is essential to reduce complications and improve overall healthcare efficiency.

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Everything You Need To Know

What is malignant biliary obstruction, and why is it important to understand the treatment options?

Malignant biliary obstruction occurs when bile ducts are blocked due to cancer, leading to significant health complications. Understanding treatment options like endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasound-guided biliary drainage (EUS-BD) is crucial because they directly impact patient outcomes, quality of life, and the overall management of the disease. Effective treatment aims to relieve the obstruction, allowing bile to flow freely and preventing complications like jaundice and infection.

How does the study by Park et al. contribute to the debate between EUS-BD and ERCP-BD for managing biliary obstruction?

The study by Park et al., published in 'Gastrointestinal Endoscopy', directly compared EUS-BD and ERCP-BD, providing a head-to-head analysis of the two methods. The study concluded that their safety profiles are similar. However, this sparked debate due to concerns about the sample size and the methods used to assess stent patency. Some experts suggest that the sample size may have been insufficient to detect meaningful differences in stent performance, and that more sophisticated statistical methods, like the Kaplan-Meier method or Cox proportional hazard model, should be used to provide a more accurate analysis of stent patency.

What are the limitations of the study by Park et al. regarding stent patency, and how could the analysis be improved?

The study by Park et al. has limitations in its assessment of stent patency. The critique suggests that stent patency should not be treated as a simple variable but analyzed using time-to-event methods such as the Kaplan-Meier method or Cox proportional hazard model. These statistical methods are designed to analyze how long stents function effectively over time, providing a more nuanced and accurate understanding of stent performance. Using these methods, a noninferiority test would likely require a larger sample size, potentially involving at least 150 patients in each group, to reliably identify any significant differences in stent patency between EUS-BD and ERCP-BD.

How does the timing of ERCP in relation to cholecystectomy (CCY) affect patient outcomes?

The timing of ERCP relative to cholecystectomy (CCY) is crucial for patient outcomes, as highlighted by the study by Suarez et al. The interval between these procedures can significantly influence hospital stays, the risk of complications, and overall patient well-being. Optimizing the timing can lead to reduced hospital stays and improved healthcare efficiency by minimizing unnecessary delays and ensuring timely interventions.

What are the main takeaways from the comparison of EUS-BD and ERCP-BD, and what future research is needed?

The primary takeaway is that while both EUS-BD and ERCP-BD are viable options for managing malignant biliary obstruction, the debate continues regarding their safety and efficacy. The study by Park et al. suggests similar safety profiles. However, concerns about the sample size and the methods used to assess stent patency underscore the need for further research. Future studies, potentially with larger sample sizes and employing advanced statistical methods like the Kaplan-Meier method or Cox proportional hazard model, are needed to definitively compare the long-term outcomes and efficacy of EUS-BD and ERCP-BD. These studies should also investigate the impact of stent type and the optimal timing of ERCP and cholecystectomy (CCY) to enhance patient outcomes and healthcare efficiency.