Review for 10.1186/s12876-022-02332-8 (2022)

Reviewer’s report
Title: 
A colorectal cancer missed by colon capsule endoscopy - A case report
Version: 
0 
Date: 
09 Feb 2022
Reviewer's report:
With great interest I have read the manuscript: 
'A colorectal cancer missed by
colon capsule endoscopy - A case report'. This case report illustrates that
colorectal cancer can be missed and clinicians should be aware of this
possibility. 
Comments 
- Were the CCE findings known to the endoscopists performing the colonoscopy
in this patient? A previous study showed that the polyp detection rate (PDR) in
CCE was higher than the PDR of colonoscopy. This study performed repeat
colonoscopies and found additional polyps during colonoscopies. This
demonstrated that polyps are easily missed during colonoscopy, especially if the
endoscopist is unaware of the CCE findings. (Kobaek-Larsen M, Kroijer R,
Dyrvig AK et al. Back-to-back colon capsule endoscopy and optical colonoscopy
in colorectal cancer screening individuals. Colorectal Dis 2018; 20: 479-485). 
- What was the experience of the reviewers of the CCE images? Previous studies
have shown that reading capsule images is associated with a high degree of
inter-observer agreement among experts. 
- Was the cecum valve objectified? The tumor was not mistaken as the valve? 
- Could the authors inform the readers with the transit times per segment? You
would expect that the transit time in the cecum was very fast, otherwise it would
be it would be hard to miss a 40 mm lesion. 
- Although CRC was missed by CCE, this had no clinical consequences for the
patient since she had an indication for colonoscopy due to multiple polyps.
- Please mention the bowel preparation scheme used for CCE and colonoscopy 
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Is the study design appropriate to answer the research question (including the use
of appropriate controls), and are the conclusions supported by the evidence
presented?
Yes
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Yes
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Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
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