Title: Breast cancer screening and early diagnosis in China: A systematic review and meta-
analysis on 10.72 million women
Version: 0 Date: 21 Oct 2023
Reviewer's report:
The manuscript entitled "Breast cancer screening and early diagnosis in China: A system
review and meta-analysis on 10.72 million women" has been read with interest to have better
understanding the current situation of breast cancer in China.  Brief summary of my comments
is shown as follows:
1. The abstract effectively communicates the research's purpose, which is to analyze  the efficacy
of breast cancer screening programs in China by applying  cancer detection rates (CDRs), early-
stage cancer detection rates (ECDRs), and proportions of early-stage cancer as the indicators
of efficacy.
2. With an appropriate study design of clearly stated inclusion criteria and the use of a random
effects model, a total of 35 researches were included. Although the authors have managed to
conduct urban/rural subgroup analysis, a list of covered administrative area in China would
be needed to help readers understand the geographic coverage of screening programs because
they may be highly associated with the economic levels and education levels of the patients/
participants, which would be a crucial issue in the social context of China.
3. Fewer participants were enrolled as "opportunistic" screening target is probably because
"opportunistic" screening requires better self-awareness  of health and socio-econmic
characteristics of the participants.  It is interesting to see the opportunistic screening are with a
higher CDR, and this may indicate a necessity to ask why and how these patients managed to
voluntarily have breast cancer screening.  The authors can elaborate the underlyinbg mechanisms
in more details.  May it  be the future direction for effective promotion program in addition to
apply more organized screening program in China?  Are certain areas with  restricted resources
for providing public health program involved in more participants receiving cancer screening
themself?
4. The limitations of the study mainly comes from the inconsistency of provided data across
publications.  i am wondering if there is consistent protocol to validate the clinical and
pathological diagnosis of breast cancer.
5.  Any practical suggestions for policies of  the Cancer Registration System in China after such
a review?
6. There are recently published paper/associated comments in Jama internal medicine
concerning cancer screening, which are suggested to be supplemented in the discussion section
of this manuscript in revision.
Reference paper:  doi:10.1001/jamainternmed.2023.3798
Minor points
1. In table 2, the proportion of early-stage (0-I/0-II) cancer may not be appropriate to be aligned
with other indicators because it may cause some confusion.  It may be needed to consistently
use  stage 0–II which are defined as early-stage breast cancer in the whole manuscript.
2. The title may need to be modified as Breast cancer screening and early diagnosis in China: A
"systematic" review and meta-analysis on 10.72 million women
3. Have this review registered online in the PROSPERO website as it is a basic requirement to
avoid duplication of systematic review?