Title: Trends and survival benefits of bilateral breast-conserving surgery in patients with
metachronous bilateral breast cancer
Version: 2 Date: 29 Jul 2024
Reviewer's report:
The topic of this article is novel and has good innovation. The author focuses on MBBC, a
relatively rare clinical condition. The SEER data in the United States can be used for analysis,
and the conclusions drawn have certain clinical reference value. At the same time, I have some
questions.
1#SEER database includes a large number of patient data, and there are different types of
database classification, I would like to know which specific database is used in this article.
As far as I know, most databases do not record the specific time of surgery, and the types of
pathology are missing Or unclear. What is the author's choice when encountering the above
missing information?
2#Is there a specific cause of death recorded in the SEER database? It's my understanding that
some of the causes of death are unclear. How is BCSS defined in this article? It is also mentioned
in this article: The median survival time could not be determined since BCSS outcomes were
available for less than 50% of the patients in the dataset. So I don't think it's convincing enough
to say that BCS remained an independent favorable prognostic factor for BCSS. Fortunately,
the authors did not mention this in the conclusion, which is a very wise choice.
3#‘Older age was positively correlated with BCS.’
I guess I'm just being pedantic. In general, younger patients are more likely to choose breast-
conserving surgery, but in this study, the opposite was true. I looked at the table and found that
the age groups were divided into three sections, which meant that patients over 65 were more
likely to choose breast-conserving surgery. This result is contrary to many studies, and if I could,
I would like to see how specific age groups choose breast conservation. Of course, this result
does not have to be reflected in the manuscript. If this is indeed the case, I think this point can
be compared with other research findings in the discussion and analyzed for reasons.
4#I'm sorry, but I think all the unknown factors that can affect the TNM stage should be ruled
out, such as positive lymph nodes. I knew that this action would affect the results of the whole
article, so it didn't matter, only 2 patients had inconclusive lymph nodes.
5#Perhaps this question is not very technical, Stage0 means no breast mass or hidden breast
cancer, in this case, how to perform a lumpectomy (BCS)? I understand that this is a factual
record of the SEER database, and I am only asking a clinical question. Of course, it does not
rule out the inaccuracy of the SEER database.
6#‘We considered whether the reason for the decline in contralateral BCS rate might be related
to patients' concern about postoperative radiotherapy for BCS.’
On this point, I remain neutral. Although radiation therapy was still immature in the early 20th
century, some studies did report cases of cancer after radiation therapy. But at present, IMRT has
been very advanced, the protection of endangered organs has been very perfect, and the United
States has been using IMRT technology since the 1970s, so I do not think that the reason for
the decline in patients' BCS is because of radiotherapy. The patients included in this study had
a large span, and differences in radiotherapy techniques in different ages could not be excluded.
Both references 21 and 22 were published in 2013. You can check the latest references for the
incidence of secondary primary cancer and heart disease after radiotherapy for breast conserving.