Review for 10.1186/s12876-020-01543-1 (2020)

Reviewer’s report
Title: 
Severe weight loss after minimally invasive oesophagectomy is associated
with poor 5-year survival in patients with oesophageal cancer
Version: 
3 
Date: 
08 Oct 2020
Reviewer's report:
PEER REVIEWER ASSESSMENTS: 
OBJECTIVE - Full research articles: is there a clear objective that addresses one
or several testable research questions? (Brief or other article types: is there a
clear objective?)
Yes - there is a clear objective
DESIGN - Is the current approach (including controls and analysis protocols)
appropriate for the objective?
Yes - the approach is appropriate
EXECUTION - Are the experiments and analyses performed with sufficient
technical rigor to allow confidence in the results?
Yes - experiments and analyses were performed appropriately
STATISTICS - Is the use of statistics in the manuscript appropriate?
Yes - appropriate statistical analyses have been used in the study
INTERPRETATION - Is the current interpretation/discussion of the results
reasonable and not overstated?
No - there are minor issues
OVERALL MANUSCRIPT POTENTIAL - Has the author addressed your
concerns sufficiently for you to now recommend the work as a technically sound
contribution? If not, can further revisions be made to make the work technically
sound?
Probably - with minor revisions
PEER REVIEWER COMMENTS: 
GENERAL COMMENTS: * Have the authors responded adequately to each of
the questions or concerns you raised in your comments?
In general yes, but I have a few minor suggestions for edits for clarity.
* Have they also made changes to reflect their responses in the manuscript
itself?
Yes, this is satisfactory with the exception of point 3 which I detail below.
* What is your overall impression of the revised manuscript?
Much improved, further minor revision/s required for clarity.
REQUESTED REVISIONS: 
Point 1 "There is still some uncertainty in that the authors state that "FT was
likely placed in
patients with deep tumour invasion who underwent preoperative therapy."
Could you make a further edit please to say that this is usual clinical practice in
patients who have deep tumour invasion and who have had preoperative therapy?
Otherwise this is still unclear.
The revision which addresses this issue in the discussion section is good.
Point 2
Categorised/organised. 
Thank you . 
It reads much better now.
Point 3
My point is that ALL of the patients in this study had severe weight loss post
operatively, even though you 
categorised them as severe or moderate weight
loss. Therefore that may be the reason why the patients in this study had poor
outcomes (weight loss and OS) regardless of whether a FT was placed or not..
The revised text in the Discussion provide does not fully address these two
points and a (minor) further revision is recommended, i.e.
a) an explanation for using a 10% weight loss as a cut off - either say that it was
selected a priori or provide a reference and please briefly discuss this choice of
10% weight loss as a cut off, in the Discussion.
b) You state that "No significant differences in the number of
18 severe weight loss patients and OS were found between the FT and no-FT
groups."
In the Discussion, please discuss whether the patients being severely
underweight may have led to an inability to see statistically significantly
differences between the FT and non FT groups in terms of OS and weight loss. 
Is it possible that patients with higher body mass at surgery do better if they have
a FT placed and are given enteral nutrition? 
That is, has the cut off of 10% been
set too high, and patients are severely underweight at the start, so a FT does not
make much difference? Please discuss this briefly.
(I apologise for my previous typographical errors in my text).
ADDITIONAL REQUESTS/SUGGESTIONS: 
Page 2 line 20, enteral nutrition did not improve severe weight loss (not 'could
not')
Page 7 line 4 the variables
Page 7 line 15 The 16 patients were *categorised into a* 
severe weight loss
group (n = 65) (more than 10% weight loss) and 
a moderate weight loss group
(less than 10% weight loss) (n = 252).
There may be other typographical and grammatical errors and I suggest a
thorough proofread before publication please.
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