Reviewer ’s report  
 
Title: Mediating effects of shoulder -arm exercise on the postoperative severity of symptoms 
and quality of life of women with breast cancer  
 
Version: 0 Date: 22 Mar 2020  
 
Reviewer: Joseph Abi Jaoude  
 
Reviewer's report:  
 
The authors presen t a cross -sectional study analyzing the QOL of patients with breast cancer 
after surgery. The study compares the QOL of patients that followed shoulder exercises, and 
those that did not.  The authors present an interesting article for many reasons. First o f all, the 
authors tackle the subject of physical exercise, which the general public (including 
physicians) tend to consider useful and beneficial, while limited data on the topic exist in 
great cancer. Second, and most importantly, the authors present a s tudy on QOL, which 
should be constantly encouraged nowadays, as QOL is one of the only 2 (along with OS) 
clinically relevant endpoints to the patients. As such, this paper, despite its many flaws, 
would be very interesting to the readers of BMC Women's Hea lth. 
 
 
Comments:  
 
Introduction: plz shorten the intro as it is too lengthy, and the general idea of adverse events 
is redundant, a few sentences on common adverse events and decreased QOL would suffice.  
 
Methods: This is a cross -sectional study, so it would obviously carry a lot of limitations and 
bias, hopefully in the future prospective studies would be implemented. This is something 
that the authors should mention more clearly in their limitations, instead of only calling for 
new prospective study. It shou ld be made clear that the study design is a limitation to the 
study. Also the conclusion should call for prospective QOL studies, as a primary endpoint.  
 
Methods: any reason why the authors picked a 90% power? This is weird as the typical 
number used is 80% , maybe add a sentence on the reason for the 90% if anything relevant.  
 
Methods: What are the 10 predictors that you assumed initially in your design?  
 
Methods: FLIC, please change "person's" to "patient's QOL"  
 
Methods: is the FLIC validated in Breast cancer ? Whether yes or no, it should be mentioned 
in text. And if not, should be added to the limitations too. It is okay to use non -validated tools 
since HRQOL are still relatively new, and thus any research on that filed should be 
encouraged. But if the tool i s not validated it should be made clear.  
 
Methods: same question for SDS -CMF.  
 
Discussion: It would be interesting if the authors could add few points on how QOL are being 
implemented. QOL are - in the majority of trials - included as secondary endpoints onl y. 
While in reality, OS and QOL are the only 2 clinically relevant patients endpoints. As such, 
one or those 2 endpoints should always be a primary endpoint in any clinical trial. More 
importantly, any trial that is practice changing should be based on one  of those 2 endpoints, 
and not surrogate endpoints, like the most commonly used PFS. The authors could add those 
points mainly focusing on QOL, and add some citations.  
 
Limitation: a major limitation to be added is the lack of comparator and baseline in the  study, 
which severely limits the interpretation of QOLs. Simply comparing QOL numbers at one 
time point between two groups (shoulder exercise vs No exercise) is definitely not enough to 
draw conclusions.  The validity of QOL measurement tools is quite com plex, and depends on 
many factors, including multiple time points, and MID, issues that are not  tackled at all bu 
the authors.  
 
Conclusion: the conclusion and take -home message should be toned down. This study is nice, 
however, the study suffers from exten sive limitations, and thus any conclusion is 
questionable. Using "could" and "may"… would be better in the conclusion, as a clear 
indication cannot be induced from this study. It is fine to have questionable outcomes, 
however this should be made clear, rat her than stating strong conclusions, that readers might 
simply take for granted. This comment also applies to the conclusion in the abstract.  
 
Conclusion: The call for future research should focus mainly on prospective, multiple -time 
points and follow -ups QOL studies, mediators like KPS would be less interesting, as the 
complete purpose of QOL, is to be a stand alone endpoint. Another really interesting call, 
would be to include more studies (mainly clinical trials) where QOL is a PRIMARY 
endpoint, and not just a secondary endpoint.  
 
Tables: Could the authors specify individual T, and N stages (no need for M, as no metastatic 
patients were recruited) instead of clumping them together into the composite stage? Adding 
tumor size (T), lymph node involvement (N)  alone would be a better way to understand the 
population. Especially N stage, as N stage play a big role on management, and subsequent 
adverse events.  
 
 
 
 
Are the methods appropriate and well described?  
If not, please specify what is required in you r 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.  
 
Unable to assess  
 
Are the conclusions drawn adequately supported by the data shown?  
If not, plea se explain in your comments to the authors.  
 
No 
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an additional statistical review is recommended, please specify 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, fees, 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 that 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?  
 
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below.  If your reply is yes to any, please give details below.  
 
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