Reviewer’s report
Title:  Effects of exercise on Inflammatory Factors and IGF System in Breast Cancer Survivors: A
Meta-analysis
Version: 0 Date: 21 Apr 2022
Reviewer's report:
*       This meta-analysis aimed to look at the effects of exercise on inflammatory and IGF factors in
breast  cancer  survivors.  This  topic  is  interesting  and  relevant.  However,  I  personally found  this
manuscript a bit disjointed and hard to follow with limitations that preclude this work from publication.
I believe that the manuscript generally should be restructured so that readers can clearly identify the
problem (cancer recurrence), solution (exercise), and questions surrounding that solution (do these
suggested mechanisms play a role in BC recurrence). In its present form, this manuscript falls short of
achieving this. I have provided more detailed comments below in an effort to assist the authors in
addressing these issues. 
*       Abstract
o       Please provide brief rationale that leads into purpose of the meta-analysis in the Background 
section
o       Define IGF 
o       Provide more detail (e.g., brief description of inclusion/exclusion criteria of articles) in methods 
portion of abstract. 
o       Results and conclusion do not address purpose / RQ's in background section of abstract. How do 
these results play a role in the prevention of breast cancer? This needs to be explicitly stated and 
addressed. 
*       Background
o       A general comment (and as a whole for other sections in the manuscript) - I do suggest 
restructuring the background section. Currently, it is very hard to follow is made up of many 
fragmented sentences and needs to be broken up into different paragraphs with distinct themes in each 
that flow from one paragraph to the next 
o       Define IGF 
o       Would suggest providing more background / rationale on the benefits of exercise that strengthen 
your rationale of examining this "treatment" on these potential mediating BC-related factors 
       An example, you mention "other meta-analyses have come to a different conclusion" yet there is 
no explanation as to what that is. Showing these contradictions with improve the rationale of 
conducting this meta-analysis, which I believe is missing from this manuscript at the moment. 
o       Page 4 - should be "reduce the risk of breast cancer" (delete "patients" at the end of the sentence)
o       From what I read in the abstract, currently the "theme"/purpose of the paper is inconsistent 
*       Methods
o       A strength of this paper is that they have registered their protocol. However, I am skeptical of the 
search terms used here. I feel as if the limited number of search terms will result in many articles being 
missed. 
       Can the authors provide a rationale as to why so few search terms were used in this instance? I 
believe this to be a major limitation of the analysis at the moment. 
o       A criteria for inclusion is post-op rehabilitation yet authors at one point do discuss this analysis as 
being important to understand mechanisms of breast cancer occurrence. Please clarify if this analysis 
focuses on cancer occurrence or recurrence as this is currently not clear. 
o       If using R-Studio - please provide/cite the R-package that was used to conduct this analysis 
*       Discussion / Results 
o       Authors discuss the uniqueness of their analysis in that it considers exercise time and type yet this
is lost or not clearly stated in the introduction section. More discussion on this earlier in the manuscript 
could strengthen its potential for publication 
o       A lot of the lit review in sections 4.1 and 4.2 should be moved to background and then referenced 
here. This type of information is missing earlier in the manuscript. And discussion needs to be more 
focused on results and interpretation / potential implication of said results.  
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Declaration of competing interests
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Is the study design appropriate to answer the research question (including the use of appropriate
controls), and are the conclusions supported by the evidence presented?
No
Are the methods sufficiently described to allow the study to be repeated?
No
Is the use of statistics and treatment of uncertainties appropriate?
Yes
Is the presentation of the work clear?
Yes
Are  the  images  in  this  manuscript  (including  electrophoretic  gels  and  blots)  free  from  apparent
manipulation?
No