Reviewer's report
Title:The value of age and medical history for predicting the likelihood of
colorectal cancer and adenomas
Version: 1Date:13 January 2011
Reviewer: William Hamilton
Reviewer's report:
Thank you for asking me to referee this paper. I can confirm I know the subject,
and that I have no conflicts of interest.
Summary
This paper describes a large cohort of patients referred for colonoscopy in an
Australian centre. It seeks to identify a scoring system (derived from a
multivariable model) to predict cancer or polyps. The results are presented as
ROC curves, and the researchers conclude their scoring system can identify
people to be triaged for colonoscopy.
Although the overall paper is of some interest, it has several drawbacks.
First, the cohort is extremely disparate; it was anyone over 18 referred for
colonoscopy. So these may have been screening colonoscopies, suspected
cancer, follow-ups. This means two things: the results only pertain to such a
heterogeneous group of patients, and that they cannot be used as a selection
method for referral for colonoscopy. The authors don’t suggest the latter, but
unless they make explicit in their title that the study is in the referred population a
reader could easily be misled. MAJOR
Second, if the aim of the paper was to create a method of triage, then the logical
outcome variable for study would be ‘condition worth identifying by colonoscopy’
as a binary variable. Their multinomial regressions (which are quite pretty) are
actually too sophisticated! RECOMMENDED
Third, other scoring systems are omitted. The SELVA score aims to do precisely
the same thing. Its creation was published in the Lancet and its validation in
Wales was published this year. I can find the reference if the authors cannot.
MAJOR
Fourth, at least one ROC curve should be shown. The key need is for a steep left
side with very low sensitivity and very high specificity – these are the patients
who may be able to avoid colonoscopy completely. I simply don’t think their table
4 results are workable in clinical practice. Medico-legally a patient referred for
colonoscopy who is not offered the service but who harbours cancer will cost the
service much more than the savings generated by triage. MAJOR
Fifth, The conclusion that FH and symptoms are poor predictors of cancer is only
true in the referred population, and even in them most studies find rectal bleeding
a positive predictor. RECOMMENDED
Finally, have the editors examined the previous publications from this cohort?
How different is this one?
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I declare that I have no competing interests
Reviewer's report
Title:The value of age and medical history for predicting the likelihood of
colorectal cancer and adenomas
Version: 1Date:13 January 2011
Reviewer: William Hamilton
Reviewer's report:
Thank you for asking me to referee this paper. I can confirm I know the subject,
and that I have no conflicts of interest.
Summary
This paper describes a large cohort of patients referred for colonoscopy in an
Australian centre. It seeks to identify a scoring system (derived from a
multivariable model) to predict cancer or polyps. The results are presented as
ROC curves, and the researchers conclude their scoring system can identify
people to be triaged for colonoscopy.
Although the overall paper is of some interest, it has several drawbacks.
First, the cohort is extremely disparate; it was anyone over 18 referred for
colonoscopy. So these may have been screening colonoscopies, suspected
cancer, follow-ups. This means two things: the results only pertain to such a
heterogeneous group of patients, and that they cannot be used as a selection
method for referral for colonoscopy. The authors don’t suggest the latter, but
unless they make explicit in their title that the study is in the referred population a
reader could easily be misled. MAJOR
Second, if the aim of the paper was to create a method of triage, then the logical
outcome variable for study would be ‘condition worth identifying by colonoscopy’
as a binary variable. Their multinomial regressions (which are quite pretty) are
actually too sophisticated! RECOMMENDED
Third, other scoring systems are omitted. The SELVA score aims to do precisely
the same thing. Its creation was published in the Lancet and its validation in
Wales was published this year. I can find the reference if the authors cannot.
MAJOR
Fourth, at least one ROC curve should be shown. The key need is for a steep left
side with very low sensitivity and very high specificity – these are the patients
who may be able to avoid colonoscopy completely. I simply don’t think their table
4 results are workable in clinical practice. Medico-legally a patient referred for
colonoscopy who is not offered the service but who harbours cancer will cost the
service much more than the savings generated by triage. MAJOR
Fifth, The conclusion that FH and symptoms are poor predictors of cancer is only
true in the referred population, and even in them most studies find rectal bleeding
a positive predictor. RECOMMENDED
Finally, have the editors examined the previous publications from this cohort?
How different is this one?
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I declare that I have no competing interests
Please review this paper.
user
Reviewer's report
Title:The value of age and medical history for predicting the likelihood of
colorectal cancer and adenomas
Version: 1Date:13 January 2011
Reviewer: William Hamilton
Reviewer's report:
Thank you for asking me to referee this paper. I can confirm I know the subject,
and that I have no conflicts of interest.
Summary
This paper describes a large cohort of patients referred for colonoscopy in an
Australian centre. It seeks to identify a scoring system (derived from a
multivariable model) to predict cancer or polyps. The results are presented as
ROC curves, and the researchers conclude their scoring system can identify
people to be triaged for colonoscopy.
Although the overall paper is of some interest, it has several drawbacks.
First, the cohort is extremely disparate; it was anyone over 18 referred for
colonoscopy. So these may have been screening colonoscopies, suspected
cancer, follow-ups. This means two things: the results only pertain to such a
heterogeneous group of patients, and that they cannot be used as a selection
method for referral for colonoscopy. The authors don’t suggest the latter, but
unless they make explicit in their title that the study is in the referred population a
reader could easily be misled. MAJOR
Second, if the aim of the paper was to create a method of triage, then the logical
outcome variable for study would be ‘condition worth identifying by colonoscopy’
as a binary variable. Their multinomial regressions (which are quite pretty) are
actually too sophisticated! RECOMMENDED
Third, other scoring systems are omitted. The SELVA score aims to do precisely
the same thing. Its creation was published in the Lancet and its validation in
Wales was published this year. I can find the reference if the authors cannot.
MAJOR
Fourth, at least one ROC curve should be shown. The key need is for a steep left
side with very low sensitivity and very high specificity – these are the patients
who may be able to avoid colonoscopy completely. I simply don’t think their table
4 results are workable in clinical practice. Medico-legally a patient referred for
colonoscopy who is not offered the service but who harbours cancer will cost the
service much more than the savings generated by triage. MAJOR
Fifth, The conclusion that FH and symptoms are poor predictors of cancer is only
true in the referred population, and even in them most studies find rectal bleeding
a positive predictor. RECOMMENDED
Finally, have the editors examined the previous publications from this cohort?
How different is this one?
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I declare that I have no competing interests
assistant