Review for 10.1186/s12876-020-01255-6 (2020)

Reviewer ’s report  
 
Title: The significance of preoperative serum carcinoembryonic antigen lev els in the prediction 
of lymph node metastasis and prognosis in locally advanced gastric cancer: A retrospective 
analysis  
 
Version: 1 Date: 18 May 2019  
 
Reviewer: Chunwei Peng  
 
Reviewer's report:  
The study is closely combined with clinical practice and has certain value. However, some 
problems need to be further corrected:  
 
1、In the first part of Results, the authors decleared that the sen sitivity and specificity of CEA 
for predicting LNM were 57% and 81.5%, respectively.From the perspective of tumor biological 
behaviors, the first step is the occurrence of gastric cancer, and the second step is the progression 
of gastric cancer with lymph node metastasis. Therefore, it seems that the authors should first 
test the sensitivity and specificity of CEA in predicting gastric cancer. If CEA is not so sensitive 
and specific in the diagnosis of gastric cancer, it is impossible to predict lymph node metastasis 
with such high sensitivity and specificity.  
 
2、The Normal reference values for CEA, CA199, and CA125 were assumed to be 3.4ng/ml, 
37U/ml, and 35U/ml, respectively. CEA &gt; 3.4 is abnormal, and conclusion showed that CEA 
&gt; 3.21 may lead to lym ph node metastasis. That is to say, some people with 3.21 &lt; CEA 
&lt; 3.4 need to consider lymph node metastasis even if CEA is normal. So what is the 
significance of setting the normal range of clinical setting? Should we consider changing the 
normal ra nge in clinic? For example, CEA &gt; 3.4 indicates a high degree of suspicion that the 
patient has cancer, while CEA &gt; 3.21 means that the patient needs to have lymph node 
metastasis. This is contradictory.  
 
3、The author's research ideas and research pop ulation should be adjusted. Firstly, the predictive 
value of CEA in the diagnosis of gastric cancer should be confirmed in the normal control 
population. Secondly, the cut -off point should be further analyzed in the abnormal population of 
CEA ( &gt;3.4), an d its predictive value for lymph node metastasis should be analyzed.  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your c omments to the authors.  
 
Unable to assess  
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
No 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in yo ur comments to the authors.  
 
Yes 
 
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 y our comments to the editors.  
 
I am able to assess the sta tistics  
 
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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