Title: Colorectal cancer pre-diagnostic symptoms are associated with anatomic cancer site
Version: 1 Date: 04 Nov 2023
Reviewer:  Amir Hakimhashemi
Reviewer's report:
Comments to the authors:
The authors attempt to link the colorectal cancer pre-diagnostic symptoms with cancer sites for a
sample of CRC-cancer diagnosed patients. My comments focus mostly on the statistical aspects.
Major comment:
- What does this paper add to the common knowledge in this area?
- For me some important issues are missing. From this study, we cannot conclude anything
about the association between observing pre-symptoms and later CRC-cancer diagnoses. I
could suggest a type of case-control study with people of different age groups, diagnosed and
undiagnosed, with and without symptoms, to investigate the association between symptoms and
CRC-cancer diagnose, especially for the early onset cases.
Minor comments:
1) There is a potential bias due to the way of patient’s recruitment. The recruiting process was
not based on a random selection. How can you guarantee that the patient sample resembles the
CRC-cancer patient population in the studied area?
2) Why the choice of age group: 20-74 years? Is this age group comprehensive for an
epidemiological study in the area of CRC-cancer?
3) You may need to apply an alpha-error-correction (p-value correction), due to multiple
statistical testing, and calculate the corrected 95% confidence intervals for the significance tests
for n parallel tests. The corrected alpha-error could be 0.05/n (Bonferroni correction).
4) Could you share the SAS-results of the logistic-regression models?
5) Could you share the first, second and third quantiles of the sample age? Does the sample age
resemble the population of CRC-cancer patients?
6) Are covariates correlated? Have you applied any correlation test? If there is a correlation,
how are you dealing with it?
7) Does the time elapsed between symptoms and diagnoses play a significant role in your model?
How could it change the results?
8) I wonder if you could test the combination of the symptoms.
9) Did you consider random effects in the regression models?
10) Table 1 caption is confusing. The first two rows do not show the numbers and percentages.
11) Line 183: The OR is not significant.
Title: Colorectal cancer pre-diagnostic symptoms are associated with anatomic cancer site
Version: 1 Date: 04 Nov 2023
Reviewer:  Amir Hakimhashemi
Reviewer's report:
Comments to the authors:
The authors attempt to link the colorectal cancer pre-diagnostic symptoms with cancer sites for a
sample of CRC-cancer diagnosed patients. My comments focus mostly on the statistical aspects.
Major comment:
- What does this paper add to the common knowledge in this area?
- For me some important issues are missing. From this study, we cannot conclude anything
about the association between observing pre-symptoms and later CRC-cancer diagnoses. I
could suggest a type of case-control study with people of different age groups, diagnosed and
undiagnosed, with and without symptoms, to investigate the association between symptoms and
CRC-cancer diagnose, especially for the early onset cases.
Minor comments:
1) There is a potential bias due to the way of patient’s recruitment. The recruiting process was
not based on a random selection. How can you guarantee that the patient sample resembles the
CRC-cancer patient population in the studied area?
2) Why the choice of age group: 20-74 years? Is this age group comprehensive for an
epidemiological study in the area of CRC-cancer?
3) You may need to apply an alpha-error-correction (p-value correction), due to multiple
statistical testing, and calculate the corrected 95% confidence intervals for the significance tests
for n parallel tests. The corrected alpha-error could be 0.05/n (Bonferroni correction).
4) Could you share the SAS-results of the logistic-regression models?
5) Could you share the first, second and third quantiles of the sample age? Does the sample age
resemble the population of CRC-cancer patients?
6) Are covariates correlated? Have you applied any correlation test? If there is a correlation,
how are you dealing with it?
7) Does the time elapsed between symptoms and diagnoses play a significant role in your model?
How could it change the results?
8) I wonder if you could test the combination of the symptoms.
9) Did you consider random effects in the regression models?
10) Table 1 caption is confusing. The first two rows do not show the numbers and percentages.
11) Line 183: The OR is not significant.
Please review this paper.
user
Title: Colorectal cancer pre-diagnostic symptoms are associated with anatomic cancer site
Version: 1 Date: 04 Nov 2023
Reviewer:  Amir Hakimhashemi
Reviewer's report:
Comments to the authors:
The authors attempt to link the colorectal cancer pre-diagnostic symptoms with cancer sites for a
sample of CRC-cancer diagnosed patients. My comments focus mostly on the statistical aspects.
Major comment:
- What does this paper add to the common knowledge in this area?
- For me some important issues are missing. From this study, we cannot conclude anything
about the association between observing pre-symptoms and later CRC-cancer diagnoses. I
could suggest a type of case-control study with people of different age groups, diagnosed and
undiagnosed, with and without symptoms, to investigate the association between symptoms and
CRC-cancer diagnose, especially for the early onset cases.
Minor comments:
1) There is a potential bias due to the way of patient’s recruitment. The recruiting process was
not based on a random selection. How can you guarantee that the patient sample resembles the
CRC-cancer patient population in the studied area?
2) Why the choice of age group: 20-74 years? Is this age group comprehensive for an
epidemiological study in the area of CRC-cancer?
3) You may need to apply an alpha-error-correction (p-value correction), due to multiple
statistical testing, and calculate the corrected 95% confidence intervals for the significance tests
for n parallel tests. The corrected alpha-error could be 0.05/n (Bonferroni correction).
4) Could you share the SAS-results of the logistic-regression models?
5) Could you share the first, second and third quantiles of the sample age? Does the sample age
resemble the population of CRC-cancer patients?
6) Are covariates correlated? Have you applied any correlation test? If there is a correlation,
how are you dealing with it?
7) Does the time elapsed between symptoms and diagnoses play a significant role in your model?
How could it change the results?
8) I wonder if you could test the combination of the symptoms.
9) Did you consider random effects in the regression models?
10) Table 1 caption is confusing. The first two rows do not show the numbers and percentages.
11) Line 183: The OR is not significant.
assistant