Review for 10.1186/s12876-020-1171-1 (2020)

Reviewer’s report
Title: Comparison of the effects of adjuvant concurrent chemoradiotherapy and chemotherapy for
resected biliary tract cancer
Version: 1 Date: 09 Jan 2020
Reviewer: Reviewer 2
Reviewer's report:
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?
Yes - the author's interpretation is reasonable
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?
Yes - current version is technically sound
PEER REVIEWER COMMENTS: 
GENERAL COMMENTS: The manuscript mainly tries to answer whether addition of radiotherapy to
adjuvant chemotherapy increases both recurrence survival and overall survival rate. 
Adjuvant treatment of biliary cancer consists of adjuvant capecitabine and no effective role of the
addition of radiotherapy was shown in prospective trials.
Therefore this study may have some important role in this area and show radiotherapy may have
benefit on RFS but their data failed to show a decrease in local recurrence rate.
The previous reviewers pointed out some technical mistakes but overall impression of the study seems
well.
The authors corrected these mistakes and the manuscript now seems to be ok.
This was a retrospective study so changing of the clinical practice and additive value to the literature is
limited. Due to scarce manuscripts about adjuvant radiotherapy, the manuscript has some value.
ADDITIONAL REQUESTS/SUGGESTIONS: 
The authors report their single center experience with a retrospective analysis, and showed that addition
of  radiotherapy statistically decreases  recurrence  free  survival,  however  has  no  effect  on  overall
survival. İnterestingly this decrease in recurrence free survival did not seem to come from a decrease in
local recurrence rate.
Therefore, this study seems to add value to the literature but due to the design of the study there are
some design-related weakness as mentioned.
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.
Yes
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
Yes
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:
Acceptable
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 publication 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 currently 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?
If you can answer no to all of the above, write 'I declare that I have no competing interests' below.
If your reply is yes to any, please give details below.
This reviewer has been recruited by a partner organization, Research Square. Reviewers with declared
or  apparent  competing  interests  are  not  utilized  for  these  reviews.  This  reviewer  has  agreed  to
publication of their comments online under a Creative Commons Attribution License attributed to
Research Square and was paid a small honorarium for completing the review  within a specified
timeframe. Honoraria for reviews such as this are paid regardless of the reviewer recommendation.
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