Review for 10.1186/s12876-018-0855-2 (2018)

Reviewer ’s report  
Title: Propensity score -matching analysis to compare clinical ou tcomes of endoscopic 
submucosal dissection for early gastric cancer i n the postoperative and non -operative stomachs  
 
Version: 0 Date: 25 Jun 2018  
 
Reviewer: Ichiro Oda  
 
Reviewer's report:  
The authors performed propensity score -matching analysis to compare clinical outcomes of 
endoscopic submucosal dissection for early gastric c ancer in the postoperative and non -operative 
stomach. Although several changes are needed to improve the overall quality of this manuscript, 
it is interesting and well written.  
 
1. In conclusions, it would be better to mention a comment on primary endpoin t.   
2. Why did the authors use those cut off values for the propensity score calculation? 75 years for 
age and 21mm for tumor size  
3. In Table 4, the numbers for "gastrectomy" and "esophagectomy" are reversed.  
4. As a terminology of gastrectomy for tumor in the remnant stomach, Japanese Gastric Cancer 
Treatment Guidelines define "completion gastrectomy" instead of "total gastrectomy". It 
would be better to use "completion gastrectomy" instead of "total gastrectomy".   
5. Please indicate what the abbreviati on (DFC) stands for.  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
Yes 
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 adequa tely 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 additional statistical review is recommende d, please speci fy what aspects require further 
assessment in your comments to the editors.  
I am able to assess the statistics  
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 a ny 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 organization 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.  
 
I declare that I have no competing interests . 
 
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to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal