Title: Factors associated with patency of self-expandable metal stents in malignant biliary
obstruction
Version: 2 Date: 04 Jun 2023
Reviewer's report:
I enjoyed reading this paper. This is a retrospective study evaluating risk factors associated
with metal stent dysfunction for patients with distal malignant biliary obstruction. I have several
concerns as follows.
1. The association between aspirin use and stent patency was previously reported, and author
needed to add this information.
2. In the uni- and multivariable analyses by cox regression model, some important factors were
not included (e.g., ECOG performance status, aspirin or ursodeoxycholic acid use, primary
cancer, primary tumor size, length of stricture, previous history of biliary drainage, current tumor
treatment).
3. This is a retrospective study included patients who underwent metal stent for unresectable
malignant tumor. In your institution, how many patients underwent plastic stent or percutaneous
biliary drainage for distal MBO during this study period.
4. The authors suggested that long SEMS was associated with short stent patency in the
multivariable model. However, it was misleading because long biliary stricture might be the
reason.
5. The majority of patients underwent partially covered SEMS placement in this study. The
authors described that these stents were chosen by the endoscopist preference. However, there
might be some strategy because most of endoscopist chose PC-SEMS in this study.
6. In the methods section, the description of sample size calculation was not clear.
7. In the results section, patient flowchart should be added.
8. Early adverse events associated with SEMS deployment were not shown.
9. Please explain clearly the meaning about perioperative bacterial colonization and intact
gallbladder.
10. About patient background, previous history of biliary drainage is important information.
11. For patients with suspected malignant biliary obstruction by imaging study, did the authors
perform direct SEMS deployment without pathological confirmation?
12. The Kaplan-Meier curves for recurrent biliary obstruction and overall survival were needed
in the Figure.
13. The authors showed causes of SEMS obstruction in the Figure 2. The time to recurrent biliary
obstruction for each cause was also needed.
Title: Factors associated with patency of self-expandable metal stents in malignant biliary
obstruction
Version: 2 Date: 04 Jun 2023
Reviewer's report:
I enjoyed reading this paper. This is a retrospective study evaluating risk factors associated
with metal stent dysfunction for patients with distal malignant biliary obstruction. I have several
concerns as follows.
1. The association between aspirin use and stent patency was previously reported, and author
needed to add this information.
2. In the uni- and multivariable analyses by cox regression model, some important factors were
not included (e.g., ECOG performance status, aspirin or ursodeoxycholic acid use, primary
cancer, primary tumor size, length of stricture, previous history of biliary drainage, current tumor
treatment).
3. This is a retrospective study included patients who underwent metal stent for unresectable
malignant tumor. In your institution, how many patients underwent plastic stent or percutaneous
biliary drainage for distal MBO during this study period.
4. The authors suggested that long SEMS was associated with short stent patency in the
multivariable model. However, it was misleading because long biliary stricture might be the
reason.
5. The majority of patients underwent partially covered SEMS placement in this study. The
authors described that these stents were chosen by the endoscopist preference. However, there
might be some strategy because most of endoscopist chose PC-SEMS in this study.
6. In the methods section, the description of sample size calculation was not clear.
7. In the results section, patient flowchart should be added.
8. Early adverse events associated with SEMS deployment were not shown.
9. Please explain clearly the meaning about perioperative bacterial colonization and intact
gallbladder.
10. About patient background, previous history of biliary drainage is important information.
11. For patients with suspected malignant biliary obstruction by imaging study, did the authors
perform direct SEMS deployment without pathological confirmation?
12. The Kaplan-Meier curves for recurrent biliary obstruction and overall survival were needed
in the Figure.
13. The authors showed causes of SEMS obstruction in the Figure 2. The time to recurrent biliary
obstruction for each cause was also needed.
Please review this paper.
user
Title: Factors associated with patency of self-expandable metal stents in malignant biliary
obstruction
Version: 2 Date: 04 Jun 2023
Reviewer's report:
I enjoyed reading this paper. This is a retrospective study evaluating risk factors associated
with metal stent dysfunction for patients with distal malignant biliary obstruction. I have several
concerns as follows.
1. The association between aspirin use and stent patency was previously reported, and author
needed to add this information.
2. In the uni- and multivariable analyses by cox regression model, some important factors were
not included (e.g., ECOG performance status, aspirin or ursodeoxycholic acid use, primary
cancer, primary tumor size, length of stricture, previous history of biliary drainage, current tumor
treatment).
3. This is a retrospective study included patients who underwent metal stent for unresectable
malignant tumor. In your institution, how many patients underwent plastic stent or percutaneous
biliary drainage for distal MBO during this study period.
4. The authors suggested that long SEMS was associated with short stent patency in the
multivariable model. However, it was misleading because long biliary stricture might be the
reason.
5. The majority of patients underwent partially covered SEMS placement in this study. The
authors described that these stents were chosen by the endoscopist preference. However, there
might be some strategy because most of endoscopist chose PC-SEMS in this study.
6. In the methods section, the description of sample size calculation was not clear.
7. In the results section, patient flowchart should be added.
8. Early adverse events associated with SEMS deployment were not shown.
9. Please explain clearly the meaning about perioperative bacterial colonization and intact
gallbladder.
10. About patient background, previous history of biliary drainage is important information.
11. For patients with suspected malignant biliary obstruction by imaging study, did the authors
perform direct SEMS deployment without pathological confirmation?
12. The Kaplan-Meier curves for recurrent biliary obstruction and overall survival were needed
in the Figure.
13. The authors showed causes of SEMS obstruction in the Figure 2. The time to recurrent biliary
obstruction for each cause was also needed.
assistant