Title: The association between mammographic density and breast cancer risk in Chinese
women: A systematic review and meta-analysis
Version: 4 Date: 23 Jan 2024
Reviewer's report:
This manuscript has been improved after revised. There are some minor comments. Also, instead
of simply saying “We have corrected them.” under majority of comments in the response letter,
it would be much appreciated if authors could specify how EXACTLY did they address the
comments in the manuscript, e.g. detailing what have you changed & where in the manuscript.
Otherwise, it will be extremely challenging to locate your changes in the revised manuscript.
Detailed comments:
Introduction:
- “…Western countries and higher than the global average3”. Please state the statistic/figure of
the global average (as the comparison of China’s rate of 3-4%.
Methods:
- “… with comparable levels of experience conducted this study”: “conducted the study” is a
very border description, it is needed to precisely describe which specific process were conduced
by these two independent reviewers, e.g. literature search, title/abstract screening, full-text
assessment, data extraction, risk of bias assessment, .etc? Please bear in mind you specifically
described “This quality assessment was done performed independently by two reviewers (S.B.
and D.S.) and the final results were based on consensus.” in the section of Quality assessment.
- Study selection: “the full texts were screened” screening refers to a brief check, “assessment”
would be a more appropriate word.
- Data collection: The authors did not mention how did they collect the outcome of interest
from each individual study, e.g. did the author collect the OR/RR from each individual study,
or did the author collect the number of cases and controls in every density category from
each individual study? Also, is the outcome of interest collection same for 3 study types? This
description is critical because it will make sense of your statistical analysis.
Statistical analysis:
- “BI-RADS II, III, or IV were compared to women with BI-RADS density I by estimating…”:
A “respectively” is best to be added between “were” and “compared”.
- “RRR” was not spelled out when it for the first time showed in the main text.
- In the Reply 12 in response letter: author stated “This is a slip of the pen, the estimate used
in the analysis was OR not RR. We have corrected them”, but in the manuscript, authors still
used RRR.
- The expression of RRR could be very tricky. The current one is better than the last version,
but it needs to be further improved. For example, I still don’t understand how the “combined”
works here, because it seems like you mixed up the meta-analysis process (combined the RRR
of each studies) and the calculation of RRR.  Because unlike the study by Antoni 2012 (https://
doi.org/10.1007/s10549-012-2362-4) which extracted RR estimates from each individual study,
you extracted CRUDE data from each individual study (as mentioned earlier in this section).
Therefore, the description in Antoni’s paper may not be applicable to your. I suggest presenting
this RRR into two or three steps rather than once-in-all: 1) relative risk, 2) ratio of relative risk
(RRR), 3) meta-analysis. Besides, an equation format may also help.
Results:
- Fig 1: “Incomplete data or statistics”: please revise the reason for it. Do you mean no relevant
data of outcomes or wrong outcome data?
- Table 1: study 4: the number of pre- and post-menopausal did not add up to the total. If this is
not a typo, an explanation is needed using a superscript.
- Publication bias: swap the ID in Appendix H and G and update its content accordingly in the
supplementary document. Because the reporting of Appendix H showed before the reporting
of Appendix G, the order of contents in the Appendices should be matched with the order they
showed in the main text.
- Fig 4 and 5: although the authors stated RRR in the text, it was still “OR” in the figure content
and figure capture. Please MAKE SURE you proofread the revised manuscript with changes
prior to the submission.
Discussion:
- “a weak association between MD and breast cancer risk was weakly found in Chinese women.”
“weekly” need to be removed. Again, please ensure you proofread the revised manuscript with
changes prior to the submission to facilitate easy reading.
- “It has been reported that Chinese women have higher PD and DA than Australian women”:
PA and DA need to be spelled out.