Review for 10.1186/s12876-020-01465-y (2020)

Reviewer’ s report
Title: The efficacy of pancreatic juice cytology with liquid-based cytology for evaluating
malignancy in patients with intraductal papillary mucinous neoplasm
Version: 2Date: 06 Jun 2020
Reviewer's report:
In this study, authors evaluated the efficacy of LBC for IPMN, which revealed higher diagnostic
accuracy compared with smear method.This paper offers novelty because there have been no previous reports about LBC for IPMN andmay provide clinical impacts for considering future indication of ERCP-based cytology.
Major:
The authors showed the evaluation of the factors contributing to the accuracy of a malignantIPMN diagnosis (Table 3). I could not find out whether this analysis was performed by the patientsof malignant IPMN (43 patients) or by all the patients (90 patients) because there was nodescription of patient number or the ratio of malignancy for this analysis in RESULTS (P11-12,Evaluating the factors contributing to the accuracy of a malignant IPMN diagnosis) and Table 3.I think that it may not be suitable for the evaluation of the factors contributing to the accuracy of amalignant IPMN diagnosis if the authors performed this analysis by all the study patients (n=90)because the sensitivity and the specificity was remarkably different (sensitivity 28%; specificity98% in Table 2).
1.The authors wrote that they used a 0.025-inch guidewire (VisiGlide2; Olympus), which was
available in Japan from 2014. On the other hand, the study period was from 2003. The authors
should re-check the description of all the devices for ERCP procedures and collecting pancreatic
juice.
2.Figure 2 shows the representative findings of the smear and LBC methods.
Figure 2 Legend indicates "PJC in patients with malignant IPMN: (A) Smear method. (B) LBC.H&E, hematoxylin and eosin staining; pancreatic juice cytology; LBC, liquid-based cytology".I wonder whether the sample of figure 2B was really stained by HE (Was it stained byPapanicolaou Staining?). I also wonder whether the sample of figure 2A was really stained by HEbecause HE is mainly used for histology. Was figure 2A stained with Diff-Quick or May-giemsa?Please re-check the condition of these pictures.I cannot find out the clear differences of Figure 2A and Figure 2B. Moreover, the picture of Figure2B was not so clear. This paper tried to show the superiority of LBC. Therefore, Figure 2 wascrucial to your argument.I recommend the authors to consult these points with pathologists because they are not included inthe author list.
3.The authors should discuss the future indication of ERCP-based cytology for surgical
candidates. The sensitivity with LBC was not high enough (40% in Table 2), while the percentage
of PEP was 12.5%, which may result in the cancel or the delay of surgery.
Minor:
1.P8. METHOD: Was saline washing performed in all cases? Is there any difference between thecases with smear method and those with LBC?2.P9. METHOD: Please add brief explanation of Cotton criteria.3.P11. Please explain the method of a serial pancreatic juice aspiration cytological examination(SPACE) in METHODS section.4.P11. Patient characteristics: "A SPACE was performed more frequently in the LBC group than inthe smear method group (Table 1)."→Please describe the percentage and the ratio of patients in the
manuscript of RESULTS.
5.Please describe the comparison between the cases with SPACE and those without SPACE interms of diagnostic ability and complication in the section of RESULTS. The authors mentioneddiagnostic ability of SPACE only in DISCUSSION (P18).6.P12. Evaluating the factors contributing to the accuracy of a malignant IPMN diagnosis: "all hadP < 0.2." →What does this sentence mean?
7.P13-14. Post-ERCP adverse events: Was there any case where surgery was cancelled or delayedbecause of PEP? Was there any case of other adverse events?8.Table 3: Please describe detailed number of patients and the ratio of malignancy in univariateanalysis.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
NoDoes the work include the necessary controls?
If not, please specify which controls are required in your comments to the authors.
YesAre the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
Unable to assessAre 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 what aspects require furtherassessment in your comments to the editors.
I am able to assess the statisticsQuality of written English
Please indicate the quality of language in the manuscript:
Needs some language corrections before being published
Declaration of competing interests
Please complete a declaration of competing interests, considering the following questions:
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