Review for 10.1186/s12876-021-01715-7 (2021)

Reviewer’s report
Title: 
Very-Low-Dose Aspirin and Surveillance Colonoscopy is Cost-effective
in Secondary Prevention of Colorectal Cancer in Individuals with Advanced
Adenomas: Network Meta-analysis and Cost-effectiveness Analysis
Version: 
0 
Date: 
25 Jan 2021
Reviewer's report:
The manuscript is overall well written but lacks further description and details on
many aspects, making interpretation of results very difficult.
The motivation, as pointed on the Introduction, was to find safe chemo-
preventive agents able to reduce or block CRC development in patients who
previously had coloretal adenomas. According to reference #8, very low doses of
aspirin are already recommended for primary chemoprevention. The authors
then, seek for secondary chemoprevention. I wonder what is the rate or the
proportion of patients who have adenomas and then progress to colorectal
carcinomas. This information should be given and discussed in the manuscript,
as a manner to show the importance of this study.
On Methods, the authors define "safety outcomes" as "Safety outcomes were the
incidence of serious adverse events (SAEs) and cardiovascular (CV) events." It
would be helpful to clarify these events on the main text and not only point them
on the supplementary file. 
On page 7, it is unclear if the "normal colon" refers to a patient who previously
had a polipectomy and now is cancer-free or if this patient has never had any
ocurrence. 
Results are also not very explanatory and the figures are difficult to interpret by
themselves. The use of a network representation on Figure 1 is misleading and is
not possible to infer efficacy, as pointed on the Results section. The network
represented gives the (wrong) impression that treatments are somehow corelated
or that effects might be corelated. 
The same holds true for Figure 2, in which the
safety and efficay should be made more clear. Maybe a different representation
would help here.
Unfortunately, I believe that the manuscript cannot be published in the present
form and without the referred information.
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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?
No
Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
Yes