Review for 10.1186/s12876-017-0612-y (2017)

Reviewer ’s report  
 
Title: Findings in Young Adults at Colonoscopy from a Hospital Service Database Audit  
 
Version: 0 Date: 02 Dec 2016  
 
Reviewer: John Wong  
 
Reviewer's report:  
 
Thank you for the opportunity to review this manuscript. This is a single center retrospective 
analysis evaluating prevalence of CRC precursor lesions among <50 vs >50 year old age groups.  
 
Comments  
- Patients with confirmed IBD, confirmed Lynch syndrome should likely be excluded as CRC 
development in these cases lik ely have a different pathogenesis than sporadic forms as 
outlined in the Introduction section  
 
- Patients with PH of CRC or polyps were included, but pathology of removed polyps during 
the prior colonoscopies were not counted towards polyp prevalence in the analysis. Eg. If 
SSA/P was found on the index colonoscopy, but the colonoscopy included in this study did 
not find a SSA/P, the original SSA/P would have been missed, and SSA/P prevalence would 
be underestimated  
 
- Prevalence of SSA/P has been reported to be  associated with various risk factors, but this 
information was not provided (Davenport et al. Modifiable lifestyle factors associated with 
risk of sessile serrated polyps, conventional adenomas and hyperplastic polyps. Gut. 2016). 
Comparability of these r isk factors among <50 and >50 age groups should be performed  
 
- Interobserver interpretation of SSA/P is variable. Please provide additional details on 
pathological review. This is in light of the comparatively lower SSA/P prevalence in this 
study. Recently,  population based studies showed a SSA/P prevalence of ~9% (IJspeert et al. 
Prevalence, distribution and risk of sessile serrated adenomas/polyps at a center with a high 
adenoma detection rate and experienced pathologists. Endoscopy. 2016 Aug;48(8):740 -6) 
 
- Consider exploring CRC stage among <50 vs >50 year olds, as there are studies reporting 
more advanced CRC stages at diagnosis in the young  
 
- Please explain "the service based" ADR was …. on age 13  
 
- Can the authors speculate why rectal bleeding in the youn g is not associated with CPL/CRC, 
in contrast to >50 year olds (?bleeding more likely due to new onset IBD diagnosis)  
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to t he authors.  
 
No 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Unable to assess  
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an additional statistical review is recommended, please specify wha t aspects require further  
assessment in your comments to the editors.  
 
I am able to assess the statistics  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Acceptable  
 
Declaration of competing interests  
Please complete a d eclaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an  
organisation that may in any way gain or lose financially from the publication of this  
manu script, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds  or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any other financial co mpeting interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below.  If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests  
 
I agree to the open peer review policy of the journal. I understand that my name will be included  
on my report to the authors and, if the manuscript is accepted for publication, my named report  
including any at tachments I upload will be posted on the website along with the authors'  
responses. I agree for my report to be made available under an Open Access Creative Commons  
CC-BY license ( http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments  
which I do not wish to be included in my named report can be included as confidential comments  
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal