Review for 10.1186/s12876-021-01672-1 (2021)

Reviewer’s report
Title: 
Routine colonoscopy may be needed for uncomplicated acute right colonic
diverticulitis
Version: 
1 
Date: 
22 Jul 2020
Reviewer's report:
PEER REVIEWER ASSESSMENTS: 
OBJECTIVE - Full research articles: is there a clear objective that addresses a
testable research question(s) (brief or other article types: is there a clear
objective)?
Yes - there is a clear objective
DESIGN - Is the current approach (including controls and analysis protocols)
appropriate for the objective?
No - there are minor issues
EXECUTION - Are the experiments and analyses performed with technical rigor
to allow confidence in the results?
No - there are minor issues
STATISTICS - Is the use of statistics in the manuscript appropriate?
No - there are issues with the statistics in the study
INTERPRETATION - Is the current interpretation/discussion of the results
reasonable and not overstated?
No - there are minor issues
OVERALL MANUSCRIPT POTENTIAL - Is the current version of this work
technically sound? If not, can revisions be made to make the work technically
sound?
Probably - with minor revisions
PEER REVIEWER COMMENTS: 
GENERAL COMMENTS: 
Overall Impression: 
Overall, the authors address a reasonable question of whether patients with right-
sided uncomplicated acute diverticulitis warrant a follow-up screening
colonoscopy to rule out associated subclinical colon cancer or adenomatous
polyps after diagnosis of acute diverticulitis by CT. Their findings that only 1
patient had an associated colon cancer (although another patient was found on
CT to also have a sigmoid colon cancer and I think should have been included in
the study of 330 patients) for an incidence of less than 1% is 
pretty good support
for the concept not to require a screening colonoscopy if only to look for a
subclinical colon cancer. But another aspect of the study is that there were 20%
of patients who were found to have an adenoma(s), raising the question of
whether a 20% incidence of adenomas, with 
another 4% found to have what
would have to be called a premalignant adenoma (2 or an additional 1% with
high grade dysplasia and another 9 or additional 3% 
with a so-called 
"advanced
adenoma 
which they do not define) is enough of an association to warrant a
screening colonoscopy. I think many patients and possibly physicians would
conclude that those incidences DO warrant a screening colonoscopy.
What have the authors done well: 
First, this is an interesting question and they certainly have a large enough
sample of patients with right-sided 
uncomplicated acute diverticulitis to obtain
reasonably representative statistics. 
In what ways does it not meet best practice: 
This study ended in 2017, but they claim that there are an additional 100 patients
during 
this time interval who were 
scheduled for a colonoscopy but at the time of
writing had not yet had it done; I think that the authors could have followed up
on those patients to further increase the numbers. Second, the one patient who
had a colon cancer (it sounds like it was 
asymptomatic) recognized at the time of
acute diverticulitis probably should have been included in the number of patients
found 
to have colon cancer. Third, it would have been nice to separate out those
>45 years old (at the time when screening colonoscopy is suggested) and those
<45 years old to determine if those with polyps were primarily the older-aged
patients.
REQUESTED REVISIONS: 
Are there additional revisions the authors should make-consider: 
1. Line 43. I really believe that you should say colon cancer or colonic
adenomatous polyps, because if you found no cancer but a 10 % incidence of
villous adenomas, 
you would then support routine colonoscopy; also the
incidence of adenomatous polyps 
is a secondary but important aim of your study.
2. Line 56. I will have to argue with you that a rate of polyps of 13.4% of an
"advanced" (and I assume by that you mean premalignant) is definitely enough
to warrant colonoscopy. Thus, I disagree with your conclusions. Do you have the
expected rate of polyps in your population for the age range you are studying
with right-sided diverticulitis? If so, the rate may not be greater than the general
population (but I doubt it!). Another 1 or 2 more cases of colonic cancer would
have changed the conclusion! 
Now, I am going to 
need to correct the above statement. When I read your
abstract, it seemed like you said that 13.4% of ALL THE PATIENTS had
advanced adenomas. You should reword line 55 as follows "with advanced
adenoma in nine of these patients for an incidence of nine in 330 patients ( 3%)
in this study with right-sided acute diverticulitis.
3. Line 69. You should also point out that only 67 patients were included in that
study.
4. Line 93. Don't you mean diverticulitis rather than cancer?
5. Line 98. What do you mean by "advanced " adenoma? Better define exactly.
Do you mean villous adenoma or adenoma with dysplastic or carcinoma-in-situ
disease?
6. Lines 112 and 113. I do not think you should delete this patient because had
you not detected it on CT, then it would have been detected in surveillance
colonoscopy, AND your interest was the simultaneous presence of diverticulitis
and colon cancer, not just incidentally diagnosed colon cancer! 
Thus, I think you
need to change the percentage of simultaneous colon cancer to two of 330
patients; one more patient will not change your conclusion and this way, no one
will challenge you on not including the patient. I understand that you might
argue that the CT showed this and thus it was reasonable to exclude this patient,
but someone will challenge you on it, so just include the patient. 
7. Lines 121-125. Did any patient have a villous adenoma? Why do you not
mention this?
8. Line 138. There are many more patients, and I would suggest that you
delineate other reasons for not having a surveillance colonoscopy, like "lost to
follow up." Also, even though this study ended in 2017, why didn't you include
the 100 patients in whom a colonoscopy was "scheduled but hadn't been done".
You need to review these patients' eventual colonoscopy before you submit this
paper.
9. Reword lines 142-143 to mean that, of the patients with polyps, about half of
the polys detected were in the right colon, because the way it is written now, one
might interpret it as if over half of the 330 patients had right colon polyps
10. Line 155-157. Did these two studies include diverticulitis only on the right
side or diverticulitis anywhere in the colon? You need to specify that exactly.
11. Shouldn't you comment on the finding that half of all of the polyps were
right-sided and how this compares with polys found in patients found to have
polyps who had screening 
colonoscopies? If the incidence is greater, then is there
some association of right-sided diverticulitis with right-sided polyps?
12. I think that you should separate the 330 patients into those >45 years of age
and those less than 45 years of age, because if the patient 
is >45, then if they
have not had a colonoscopy, they should have one as a general screening exam;
likewise, if they are younger than 45 and the incidence of polyps is dramatically
less and there is no history of colon cancer in the family, then the argument to
avoid a routine follow-up colonoscopy can be made with more confidence. 
13. Table 1 - when you say location of the lesion, I would change it to location
of the acute diverticulitis.
14. Finally, does an incidence of adenoma of 20% justify a routine colonoscopy?
I would suggest that you leave the decision whether to suggest routine
colonoscopy up to the discussion between the patient and the physician. If there
is a family history, then colonoscopy is warranted. In contrast, whether there is
or is not a family history in those over the age of 45 and if they have never had a
screening colonoscopy, then a very strong argument can be made that, yes, they
should have a colonoscopy or at the least a stool ColoGuard colon cancer test.
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No
Are the methods appropriate and well described?
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No
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No
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No
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