Review for 10.1186/s12876-020-1167-x (2020)

Reviewer ’s report  
 
Title: The prognostic role of platelet -to-lymphocyte ratio on overal l survival in gastric cancer: a 
systematic review and meta -analysis  
 
Version: 0 Date: 14 May 2019  
 
Reviewer: Yongxi Song  
 
Reviewer's report:  
Major revision  
 
Cao et al. conducted a meta -analysis of prognostic role of platelet -to-lymphocyte ratio on overall 
survival in gastric cancer . 
 
Comments:  
1. In Abstract, the authors stated "it remains controversial in gastric cancer", but there are 
several published meta -analysis (PMID: 27684077, 27409665, 24968121) and the results already 
showed that elevated PLR was a significant prognostic b iomarker for poor OS in gastric cancer. 
And compared with the published meta -analysis, the advantage of this study is?  
2. Search Strategy, ["PLR" OR "platelet lymphocyte ratio" AND "gastric cancer" OR 
"stomach cancer" AND "prognosis" OR "survival"]. Author s should use "()" to correct the search 
strategy. And According to the Preferred Reporting Items for Systematic Reviews and Meta -
Analysis Statement, authors should detailed show the search result for each database using 
PRISMA flowchart.  
3. "Heterogeneity among included studies was calculated using the I -square and Q statistics, 
with P &lt;0.10 indicating significant heterogeneity [16, 17]." A significant heterogeneity was 
assessed by I -square and Q statistics, simultaneously. A simple P value may be unsuita ble. 
4. The author assessed the prognostic significance of PLR on OS. As secondary outcome for 
most trials, DFS or PFS should be evaluated. Moreover, authors should assess the 
clinicopathological significance of PLR in gastric cancer.  
5. Heterogeneity. The  results of subgroup analysis were showed in Table 3, and there was 
significant heterogeneity in several subgroup analyses. Thus, the pooling HRs with massive 
heterogeneity may be not appropriate and the source of heterogeneity should be explored.  
6. Typos need to be corrected throughout the manuscript.  
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 adequately supported by the data shown?  
If not, please explain in your comments to t he 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 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:  
 
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'  
 
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 for publication, my named re port 
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 license ( http://creativecommons.org/licenses/by/4.0/ ). I underst and 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 policy of the journal