Review for 10.1186/s12876-020-01340-w (2020)

Reviewer ’s report  
 
Title: The outcomes of modified endoscopic mucosal rese ction and endoscopic submucosal 
dissection for the treatment of rect al neuroendocrine tum ors and the value of endoscopic 
morphology classification in endoscopic resection  
 
Version: 0 Date: 23 Apr 2020  
 
Reviewer's report:  
 
Wang X. et al. investigated about the out comes of modified EMR and ESD for rectal NETs. 
There were many previous reports which compare EMR and ESD for rectal NETs. However, 
their strength were large scale and using Propensity -score matching. On the other hand, this 
study was a single -center retro spective study. Therefore, reason for selection of methods of 
endoscopic treatment was unclear. Moreover, how to select which methods of modified EMR 
was also unclear. On the other hand, upper size of including cases of modified EMR were 10 
mm. So, based o n this investigation, they can't mention about treatment for NET &gt;10mm. 
There are come comments and questions for this report to improve manuscript.  
 
 
Major comments:  
 
1) In abstract, they concluded in second sentence "ESD could be used for treating rectal 
NETs with diameter between 1to 2cm after careful preoperative examination". I think based on 
this investigation this conclusion could not mentioned.  
 
2) In method section (Page 9, Line 24), EMR -L was explained "snaring below the band". 
This procedure was firstly reported as ESMR -L by Ono A. and Fujii T. for rectal carcinoids. 
Please refer this article; Gastrointest Endosc. 2003; 57: 583 -587. 
 
3) In method section (Page 10, L ine 20), they mentioned about histopathological 
evaluation. How about immunohistochemistry analysis about Ki -67 for WHO grading and 
lympho -vascular invasion such as D2 -40 and CD31. These staining seemed to be very important 
for evaluating risk of metastase s. So, please mention about them.  
 
4) In results section (Page 12, Line 1), they explained definition about endoscopic 
morphology type. Please transfer it to method section. Moreover, please describe how to classify 
such as retrospective or real time or sin gle or multi investigator.  
 
5) They include cases NETs less than 2cm. However, several guidelines recommended 
endoscopic resection (ER) for rectal NETs ≦1cm. NANETS(2012), ENETS(2016 update) both 
recommended ER for NETs ≦1cm. Only NCCN guideline (2019) all owed ER for NETs ≦2cm 
after radiological assessment. Many previous reports mentioned about the risk of metastases 1 -
2cm NETs. So please add in discussion about controversy on indication of ER for rectal NETs.  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comm ents 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 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 additional 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:  
 
Needs some language corrections before being published  
 
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 financially from the 
publi cation 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 curr ently 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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