Review for 10.1186/s12876-020-01457-y (2020)

Reviewer ’s report  
 
Title: Underwa ter versus conventional endoscopic mucosal resection  for small size 
nonpedunculated colorectal polyps ：A randomized controlled trial  
 
Version: 0 Date: 23 Apr 2020  
 
Reviewer's report:  
 
Thank you for giving me a chance to review this article. This article analyzed the data in patients 
with colorectal polyps who underwent under water EMR and conventional EMR. I have some 
comments as follows.  
Diminutive and small polyps (le ss than 9mm in size) are indicated for cold snare polypectomy 
because of its safety and high rate of complete resection rate. This had been already proved by 
some randomized controlled trials. I don't know why the authors compare the results of resection 
rate of under water EMR with conventional EMR. If the author would like to evaluate the 
efficacy of under water EMR, they should compare under water EMR with cold snare 
polypectomy not with conventional EMR.  
  
 
Comments to the Author  
 
Major comments  
1. Thi s is a non -inferiority randomized controlled trial comparing underwater EMR with 
conventional EMR.  
If the Confidence Interval (CI) lies entirely below the margin, non -inferiority of the underwater 
EMR to the conventional EMR can be concluded.  
However, in this study, it is not clear whether non -inferiority of under water EMR was 
demonstrated or not because there is no clear explanation of the upper limits of the CI.  
The upper limits of the CI exceed the non -inferiority margin?  
 
2. The Consolidated Standards  of Reporting Trials (CONSORT) Statement for non -inferiority 
and equivalence trials also recommends adding a figure showing where the CI lies with regard to 
the margin. The author should add this figure.  
 
3. The definition of complete resection rate is unclear. Is the complete resection rate defined as 
en-block resection with no residual tumor after two - sided biopsy? The two cold forceps biopsies 
were obtained from all cases?  
 
Thank you for giving me a cha nce to review this article. This article analyzed the data in patients 
with colorectal polyps who underwent under water EMR and conventional EMR. I have some 
comments as follows.  
Diminutive and small polyps (less than 9mm in size) are indicated for cold sn are polypectomy 
because of its safety and high rate of complete resection rate. This had been already proved by 
some randomized controlled trials. I don't know why the authors compare the results of resection 
rate of under water EMR with conventional EMR. If the author would like to evaluate the 
efficacy of under water EMR, they should compare under water EMR with cold snare 
polypectomy not with conventional EMR.  
  
 
Comments to the Author  
 
Major comments  
1. This is a non -inferiority randomized controlled t rial comparing underwater EMR with 
conventional EMR.  
If the Confidence Interval (CI) lies entirely below the margin, non -inferiority of the underwater 
EMR to the conventional EMR can be concluded.  
However, in this study, it is not clear whether non -inferi ority of under water EMR was 
demonstrated or not because there is no clear explanation of the upper limits of the CI.  
The upper limits of the CI exceed the non -inferiority margin?  
 
2. The Consolidated Standards of Reporting Trials (CONSORT) Statement for n on-inferiority 
and equivalence trials also recommends adding a figure showing where the CI lies with regard to 
the margin. The author should add this figure.  
 
3. The definition of complete resection rate is unclear. Is the complete resection rate defined a s 
en-block resection with no residual tumor after two - sided biopsy? The two cold forceps biopsies 
were obtained from all cases?  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
No 
 
Are you able to assess any statistics in the manus cript or would you recommend an 
additional statistical review?  
If an additiona l statistical review is recommended, please speci fy what aspects require further 
assessment in your comments to the editors.  
 
I recommend additional statistical review  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1.  Have you in the past five years received reimbursements, f ees, funding, or salary 
from an organisation that may in any way gain or lose financial ly from the 
publication of this manuscript, either now or in the future?  
 
2.  Do you hold any stocks or shares in an organisation t hat may in any way gain or 
lose financially from the publication of this manuscript, either now or in  the 
future?  
 
3.  Do you hold or are you currently applying for any patents  relating to the content 
of the manuscript?  
 
4.  Have you received reimbursements, fees, funding, or salary from an org anization 
that holds or has applied for patents relating to the content of the manuscript?  
 
5.  Do you have any other financial competing interests?  
 
6.  Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I  declare that I have  no competing interests' 
below. If your reply is yes to any, please give details below.  
 
Nothing declared  
 
I agree to the open peer review policy of the journal. I understan d that my name will be included 
on my report to the authors and, if the manuscript is accepted f or publication, my named report 
including any attachments I upload will be posted on the website along with the authors' 
responses. I agree for my report to be made available under an Open Access Creative Commons 
CC-BY licens e (http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments 
which I do not wish to be included in my named report can be in cluded as confidential comments 
to the editors, which will not be published.  
 
I agree to the open peer review poli cy of the journal