Title: Evaluating the predictive performance of gut microbiota for the early-stage colorectal
cancer
Version: 3 Date: 06 Nov 2022
Reviewer:  Ahmed Nassar
Reviewer's report:
Thank you for submitting your study assessing the role of gut microbiota as a potential screening
tool to detect early CRC. This is a very interesting topic. However, in my opinion , it needs a
significant revision.
Major issues
How the study defined early CRC?
What are stages and sites of CRC in patients included in the study?
What is the specific rationale of selecting these two types of microbiotas (S. bovis and F.
nucleatum) ?
Need for more clarification about how sensitivities/specificities has been estimated without
knowing the patient’s disease status.
Was there any comparisons between gut microbiota and FIT or FOBT as a screening test? Need
to comment on this in discussion section.
Reading the methods section, I had the impression that this is a prospective study . However,
you mentioned in the first line that , this is a retrospective study. Can you , please explain in
more details how patients were  selected (you mentioned random sampling) ? Do you perform
routine stool sampling regardless of the study? And this is why you were able to look back at
the microbiome results? Can you , please clarify this?
Minor issues:
Missing references in introduction section:
Line 49:   ‘’More surprisingly, the increasing CRC mortality in some parts of the world indicates
that early diagnosis rate was low. ‘’
Line 52: ‘’The mean five-year survival rate for those with the earliest stage (stage I) can be high
as 90%, while for CRC patients with the advanced stage (stages III and IV), it can be less than
10%. ‘’
Line 80: ‘’Some of the studies have identified that there is a correlation between S. bovis
presence in stool and colorectal neoplasia.’’
Line 81: ‘’In addition to the strong clinical correlation, recent published articles have declared
that colon cancer development is promoted actively by S. bovis via #-catenin signalling
pathway.’’
Line 92: ‘’ To overcome no gold standard situations in diagnostic accuracy research, different
statistical techniques have been proposed. As reported by large studies, latent class models
(LCMs) have been increasingly utilized to assess the accuracy of diagnostic tests in which it is
not assumed that the test is perfect’’
Line 100: ‘’ Previous research studies have already demonstrated an association between the
bacterial markers and CRC’’
Review this sentence in line 114 : ‘’ The colonoscopy was used for total participants and they
were confirmed by an expert pathologist.’’
Line 222: ‘’ It is important to note that based on the GS test’s results, of 83 participants, 47
(56.6%) subjects were at risk of CRC and the remaining 36 (43.4%) people were not.
‘’ What do you mean by subjects at risk of CRC?
Was there any data or correlation of presence of microbiota with presence of adenomas?
Please review and correct all typos and grammatical errors.
Title: Evaluating the predictive performance of gut microbiota for the early-stage colorectal
cancer
Version: 3 Date: 06 Nov 2022
Reviewer:  Ahmed Nassar
Reviewer's report:
Thank you for submitting your study assessing the role of gut microbiota as a potential screening
tool to detect early CRC. This is a very interesting topic. However, in my opinion , it needs a
significant revision.
Major issues
How the study defined early CRC?
What are stages and sites of CRC in patients included in the study?
What is the specific rationale of selecting these two types of microbiotas (S. bovis and F.
nucleatum) ?
Need for more clarification about how sensitivities/specificities has been estimated without
knowing the patient’s disease status.
Was there any comparisons between gut microbiota and FIT or FOBT as a screening test? Need
to comment on this in discussion section.
Reading the methods section, I had the impression that this is a prospective study . However,
you mentioned in the first line that , this is a retrospective study. Can you , please explain in
more details how patients were  selected (you mentioned random sampling) ? Do you perform
routine stool sampling regardless of the study? And this is why you were able to look back at
the microbiome results? Can you , please clarify this?
Minor issues:
Missing references in introduction section:
Line 49:   ‘’More surprisingly, the increasing CRC mortality in some parts of the world indicates
that early diagnosis rate was low. ‘’
Line 52: ‘’The mean five-year survival rate for those with the earliest stage (stage I) can be high
as 90%, while for CRC patients with the advanced stage (stages III and IV), it can be less than
10%. ‘’
Line 80: ‘’Some of the studies have identified that there is a correlation between S. bovis
presence in stool and colorectal neoplasia.’’
Line 81: ‘’In addition to the strong clinical correlation, recent published articles have declared
that colon cancer development is promoted actively by S. bovis via #-catenin signalling
pathway.’’
Line 92: ‘’ To overcome no gold standard situations in diagnostic accuracy research, different
statistical techniques have been proposed. As reported by large studies, latent class models
(LCMs) have been increasingly utilized to assess the accuracy of diagnostic tests in which it is
not assumed that the test is perfect’’
Line 100: ‘’ Previous research studies have already demonstrated an association between the
bacterial markers and CRC’’
Review this sentence in line 114 : ‘’ The colonoscopy was used for total participants and they
were confirmed by an expert pathologist.’’
Line 222: ‘’ It is important to note that based on the GS test’s results, of 83 participants, 47
(56.6%) subjects were at risk of CRC and the remaining 36 (43.4%) people were not.
‘’ What do you mean by subjects at risk of CRC?
Was there any data or correlation of presence of microbiota with presence of adenomas?
Please review and correct all typos and grammatical errors.
Please review this paper.
user
Title: Evaluating the predictive performance of gut microbiota for the early-stage colorectal
cancer
Version: 3 Date: 06 Nov 2022
Reviewer:  Ahmed Nassar
Reviewer's report:
Thank you for submitting your study assessing the role of gut microbiota as a potential screening
tool to detect early CRC. This is a very interesting topic. However, in my opinion , it needs a
significant revision.
Major issues
How the study defined early CRC?
What are stages and sites of CRC in patients included in the study?
What is the specific rationale of selecting these two types of microbiotas (S. bovis and F.
nucleatum) ?
Need for more clarification about how sensitivities/specificities has been estimated without
knowing the patient’s disease status.
Was there any comparisons between gut microbiota and FIT or FOBT as a screening test? Need
to comment on this in discussion section.
Reading the methods section, I had the impression that this is a prospective study . However,
you mentioned in the first line that , this is a retrospective study. Can you , please explain in
more details how patients were  selected (you mentioned random sampling) ? Do you perform
routine stool sampling regardless of the study? And this is why you were able to look back at
the microbiome results? Can you , please clarify this?
Minor issues:
Missing references in introduction section:
Line 49:   ‘’More surprisingly, the increasing CRC mortality in some parts of the world indicates
that early diagnosis rate was low. ‘’
Line 52: ‘’The mean five-year survival rate for those with the earliest stage (stage I) can be high
as 90%, while for CRC patients with the advanced stage (stages III and IV), it can be less than
10%. ‘’
Line 80: ‘’Some of the studies have identified that there is a correlation between S. bovis
presence in stool and colorectal neoplasia.’’
Line 81: ‘’In addition to the strong clinical correlation, recent published articles have declared
that colon cancer development is promoted actively by S. bovis via #-catenin signalling
pathway.’’
Line 92: ‘’ To overcome no gold standard situations in diagnostic accuracy research, different
statistical techniques have been proposed. As reported by large studies, latent class models
(LCMs) have been increasingly utilized to assess the accuracy of diagnostic tests in which it is
not assumed that the test is perfect’’
Line 100: ‘’ Previous research studies have already demonstrated an association between the
bacterial markers and CRC’’
Review this sentence in line 114 : ‘’ The colonoscopy was used for total participants and they
were confirmed by an expert pathologist.’’
Line 222: ‘’ It is important to note that based on the GS test’s results, of 83 participants, 47
(56.6%) subjects were at risk of CRC and the remaining 36 (43.4%) people were not.
‘’ What do you mean by subjects at risk of CRC?
Was there any data or correlation of presence of microbiota with presence of adenomas?
Please review and correct all typos and grammatical errors.
assistant