Review for 10.1186/1471-230X-14-187 (2014)

Reviewer's report
Title:Metabolic factors haste colorectal adenoma recurrence
Version:3Date:6 May 2014
Reviewer: Linda JW Bosch
Reviewer's report:
The manuscript by Taniguchi et al presents the results of a retrospective
multicenter study in which metabolic risk factors were evaluated against the
development of recurrent colorectal adenomas two years after removal of
adenomas at screening colonoscopy. The authors show that, besides known
histopathological characteristics of adenomas, metabolic factors BMI,
hypertension, fasting blood glucose levels and low-density lipoprotein cholesterol
levels were associated with a higher probability of adenoma recurrence.
The results are of interest for the evaluation of surveillance strategies and offer
additional insight about factors influencing the risk of adenoma recurrence. The
large number of patients evaluated in this study is of value.
Major Compulsory Revisions
1) It is not clear from the manuscript whether the metabolic factors hypertension,
DM and dyslipidemia are current factors or past history. The discussion suggests
they are past history (“Multivariate analysis identified elevated FBG was more
statistically significant than a past history of DM as a risk factor for adenoma
recurrence”), but this is not clear from the Methods section.
2) As to 1: if hypertension, DM and dyslipidemia are current metabolic factors,
there is collinearity among the independent risk factors in the multivariate logistic
analysis: i.e. diagnosis of DM is based on FBG levels, dyslipidemia is based on
TG and HDL-C levels. These factors are simultaneously put in the model, which
will affect the outcome of the multivariate logistic analysis.
3) The multiple logistic regression analysis does not show possible interactions
between variables. Have the authors looked at the different metabolic risk factors
in females vs males? And in different age groups? (e.g. <60 year vs >60 year)
4) Are there any differences in recurrence rates between the different hospitals?
5) Is there any difference in adenoma morphogy (flat, polypoid, serrated)
between the recurrent and non-recurrent group?
6) It would be interesting to add information on the characterisitcs of the recurrent
adenomas.
7) The discussion section is rather long and should be more concise.
8) Conclusion last sentence:
This study did not show that a shorter surveillance interval for colonoscopy after
removal of adenomas in high-risk patients than that proposed by the AGA
guidelines may be safer. This is an assumption and recommendation instead.
Please rephrase.
Minor Essential Revisions
1) Background, first paragraph:
“ Surveillence colonoscopy is also recommended after the initial endoscopic
screening, because of the possibility of development of new tumors.” For clarity,
please replace “screening” by “polypectomy” or “ removal of adenoma”.
2) Background, second paragraph:
Usually, advanced adenomas are classified as adenomas that show high-grade
dysplasia or >20% villous component or measure # 1 cm in size.
3) It is not clear to me in what way FBG, TC, HDL-C, LDL-C and TG values were
used in the multiple regression analysis model (i.e. “in case the values were
elevated to 10 mg/dL”). Do the authors mean that the OR refers to an increase of
the variables with steps of 10mg/dL? Please, rephrase.
4) Table 1: This table includes baseline clinical characteristics of the patients as
well as histopathological characteristics of the removed adenomas --- for a better
overview of the data, please adapt the title or subdivide the table.
5) A recently published article report on metabolic factors and adenoma
recurrence as well and should be referred to; Orannapalai N et al, Predicting the
occurrence of cancer-associated colorectal polyp using a metabolic risk score.
Mol Clin Oncol. 2014 Jan;2(1):124-128. Epub 2013 Oct 21.
Discretionary Revisions
1) I would suggest a more scientific phrasing for “haste” (e.g. in the title
“metabolic factors haste colorectal adenoma recurrence”).
2) Background, second paragraph:
The last sentence (“Features of the removed adenomas […] and multiple
number”) is redundant; the information is already covered in that paragraph by
describing patients that are classified into the high-risk group.
3) Background, fifth paragraph:
“Some studies have shown that metabolic factors […]” It would be nice for the
reader to give some examples of metabolic factors here.
4) Background, last paragraph:
Which additional risk factors? (+ reference)
5) Discussion, fourth paragraph:
“The main pathophysiological abnormality associated with the metabolic factors
is visceral fat deposistion.” Replace “the” by “increased levels of”
6) Discussion, fifth paragraph:
“[…], the cutoff value of FBG was determined to be 110 mg/dl and not 126 mg/dl
by ROC analysis, which may mean […]”. It would be nice to explain with a few
words the 126 mg/dl cutoff, since this is not common knowledge.
Level of interest: An article of importance in its field
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests