Title: Effectiveness of switching endoscopists for repeat surveillance colonoscopy: a
retrospective study
Version: 0 Date: 03 Jul 2023
Reviewer's report:
In this article, Okada et al. demonstrated tandem colonoscopy  within three months  by different
endoscopists may  significantly improve  detection of missed lesions from index colonoscopy.
While this study is interesting has its novelty, I have several concerns here:
1. In this article, the main indication for tandem colonoscopy is scheduled EMR for large polyp
during index colonoscopy. On the one hand, the lower missed lesion detection rate of the same
endoscopist can be easily explained due to mental factors; namely, the same endoscopist may
be confident to his/her own indext colonoscopy findings which leads to lesion underdetection
during the second exam. On the other hand, the scenario is quite different from surveillance
colonoscopy, in which the main task of the endoscopist is to find as many polyps as possible
rather than removing the large polyp.
Briefly, I strongly doubt if the findings in  this study can be applied into surveillance colonoscopy
since the two scenarios are highly different.
2.Furthermore, the baseline adenoma detection rate may also impact the results of second
colonoscopy. Since the reason of second procedure is to remove large polyp(s), it is likely the
procedure is performed by an experienced endoscopist. Without the baseline characteristics of
index colonoscopy and the average performance of the first and second operator, it is impossible
to conclude that the changing endoscopists leads to a better result. In fact, the better result by
a second endoscopist may be due to poor performance in the index colonoscopy. The authors
have to provide more evidence to support their argument.
3.The missed lesion detection rate in group D is above 60%, which is much higher than average
colonoscopy adenoma detection rate. This also raises my previous concern that the "good"
performance of the second endoscopist is actually attributed to poor performance by the first one.
I hope the authors can provide more solid evidence, for example, the findings of index
colonoscopy and respective adenoma detection rate of endoscopists in different groups in order
to strengthen the arguments.
Title: Effectiveness of switching endoscopists for repeat surveillance colonoscopy: a
retrospective study
Version: 0 Date: 03 Jul 2023
Reviewer's report:
In this article, Okada et al. demonstrated tandem colonoscopy  within three months  by different
endoscopists may  significantly improve  detection of missed lesions from index colonoscopy.
While this study is interesting has its novelty, I have several concerns here:
1. In this article, the main indication for tandem colonoscopy is scheduled EMR for large polyp
during index colonoscopy. On the one hand, the lower missed lesion detection rate of the same
endoscopist can be easily explained due to mental factors; namely, the same endoscopist may
be confident to his/her own indext colonoscopy findings which leads to lesion underdetection
during the second exam. On the other hand, the scenario is quite different from surveillance
colonoscopy, in which the main task of the endoscopist is to find as many polyps as possible
rather than removing the large polyp.
Briefly, I strongly doubt if the findings in  this study can be applied into surveillance colonoscopy
since the two scenarios are highly different.
2.Furthermore, the baseline adenoma detection rate may also impact the results of second
colonoscopy. Since the reason of second procedure is to remove large polyp(s), it is likely the
procedure is performed by an experienced endoscopist. Without the baseline characteristics of
index colonoscopy and the average performance of the first and second operator, it is impossible
to conclude that the changing endoscopists leads to a better result. In fact, the better result by
a second endoscopist may be due to poor performance in the index colonoscopy. The authors
have to provide more evidence to support their argument.
3.The missed lesion detection rate in group D is above 60%, which is much higher than average
colonoscopy adenoma detection rate. This also raises my previous concern that the "good"
performance of the second endoscopist is actually attributed to poor performance by the first one.
I hope the authors can provide more solid evidence, for example, the findings of index
colonoscopy and respective adenoma detection rate of endoscopists in different groups in order
to strengthen the arguments.
Please review this paper.
user
Title: Effectiveness of switching endoscopists for repeat surveillance colonoscopy: a
retrospective study
Version: 0 Date: 03 Jul 2023
Reviewer's report:
In this article, Okada et al. demonstrated tandem colonoscopy  within three months  by different
endoscopists may  significantly improve  detection of missed lesions from index colonoscopy.
While this study is interesting has its novelty, I have several concerns here:
1. In this article, the main indication for tandem colonoscopy is scheduled EMR for large polyp
during index colonoscopy. On the one hand, the lower missed lesion detection rate of the same
endoscopist can be easily explained due to mental factors; namely, the same endoscopist may
be confident to his/her own indext colonoscopy findings which leads to lesion underdetection
during the second exam. On the other hand, the scenario is quite different from surveillance
colonoscopy, in which the main task of the endoscopist is to find as many polyps as possible
rather than removing the large polyp.
Briefly, I strongly doubt if the findings in  this study can be applied into surveillance colonoscopy
since the two scenarios are highly different.
2.Furthermore, the baseline adenoma detection rate may also impact the results of second
colonoscopy. Since the reason of second procedure is to remove large polyp(s), it is likely the
procedure is performed by an experienced endoscopist. Without the baseline characteristics of
index colonoscopy and the average performance of the first and second operator, it is impossible
to conclude that the changing endoscopists leads to a better result. In fact, the better result by
a second endoscopist may be due to poor performance in the index colonoscopy. The authors
have to provide more evidence to support their argument.
3.The missed lesion detection rate in group D is above 60%, which is much higher than average
colonoscopy adenoma detection rate. This also raises my previous concern that the "good"
performance of the second endoscopist is actually attributed to poor performance by the first one.
I hope the authors can provide more solid evidence, for example, the findings of index
colonoscopy and respective adenoma detection rate of endoscopists in different groups in order
to strengthen the arguments.
assistant