Review for 10.1186/s12876-019-1096-8 (2019)

Reviewer’s report
Title: Indications for adjuvant chemotherapy in patients with AJCC stage IIa T3N0M0 and T1N2M0
gastric cancer—an east and west multicenter study
Version: 0 Date: 17 Aug 2019
Reviewer: Emanuele Lo Menzo
Reviewer's report:
I  congratulate  the  authors  for  the  manuscript  entitled:"  Indications  for  adjuvant  chemotherapy in
patients with AJCC (7th ed.) stage IIa T3N0M0 and T1N2M0 gastric cancer - an east and west,
multicenter study"
In  the  manuscript  the  authors  compare  patients  from  the  Surveillance,  Epidemiology,and  End
Results(SEER) database and the databases from Fujian Medical University Union Hospital(FJUUH)
and the Italian IMIGASTRIC center to determine the ideal role of adjuvant chemotherapy. 
Major Compulsory Revisions
1-Your objective was to determine the ideal indications of adjuvant chemotherapy(AC) in patients
with stage IIa gastric cancer (T3N0M0 and T1N2M0). However, I have concerns that this objective can
be accomplished using epidemiological databases with several missing data points.
2-There is a big disparity between the AC group (Group C) (n = 287) and the non-AC group
(Group N) (n = 1306). Can you please comment on the potential impact on you results?
3-Since in the Eastern countries AC is not recommended in T3N0M0 and T1N2M0, these patients
treated with AC in the FJUUH database (198) might have had other reasons for having AC. Can you
offer some potential explanations? 
4-I believe it is necessary to mention as a limitation the fact that the variables not mentioned in
the SEER database were not included in the analysis.
5-Do you have any information on the type of resection these patients had? That is a major
variable missing in your study. Without this data, your conclusions might be skewed.
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.
No
Are the conclusions drawn adequately supported by the data shown?
If not, please 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 recommend additional statistical review
Quality of written English
Please indicate the quality of language in the manuscript:
Acceptable
Declaration of competing interests
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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?
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