Review for 10.1186/s12876-020-01459-w (2020)

Reviewer’ s report
Title: Liver fibrosis assessments using FibroScan, Virtual-Touch tissue quantification, the FIB-4
index, and Mac-2 binding protein glycosylation isomer levels compared with pathologicalfindings of liver resection specimens in patients with hepatitis C infection
Version: 1Date: 05 Mar 2020
Reviewer's report:
Ueda et al investigated the diagnostic performances of four diagnostic modalities, namely
FibroScan, Virtual-Touch tissue quantification (VTQ), the FIB-4 index, and Mac-2 binding proteinglycosylation isomer (M2BPGi) levels for predicting liver fibrosis stage. They used surgicallyresected liver specimens for the histological staging of liver fibrosis according to the METAVIRsystem (normal, n = 14; HCV with SVR, n = 20; HCV with non-SVR, n = 74). They demonstratedthat all four diagnostic modalities correlated significantly with the histological fibrosis stages.They determined the AUROC, sensitivity, specificity, PPV, and NPV for the optimal cut-off fordichotomizing various fibrosis stages of each of these four modalities. They also demonstrated thatFibroScan and VTQ performed better than did the blood test-based modalities. Although thisstudy used surgically resected liver specimens for determining liver fibrosis stage to overcome thedisadvantages associated with percutaneously acquired liver biopsy specimens, there are severalcritical issues that need to be addressed before the conclusion can be reached.
Major Comments:
1. The most important issue for this study is to separate the liver specimens derived from patientswith SVR to anti-HCV therapy (n = 20) from those with non-SVR to anti-HCV therapy (n = 74)for assessment of liver fibrosis through these four diagnostic modalities. The cut-offs for
dichotomizing fibrosis stage proposed in previous studies are derived from patients prior to
receiving anti-viral therapy. Recent studies have shown that liver stiffness measurement throughFibroScan or ARFI and liver fibrosis indices such as FIB-4 and APRI decreased rapidly followingantiviral therapy in patients with chronic hepatitis C (Bachofner JA et al, Liver Int 2017; 37: 369-376; Chen SH et al, PLoS ONE 2018; 13: e0190455). The decreases in these parameters parallelthe resolution in hepatic necroinflammation, suggesting that these measurements reflect acombined effect of necroinflammation and hepatic fibrosis. In this regard, a recent study throughARFI elastography showed that the cut-off for predicting liver fibrosis in the post-SVR patientswas lower compared with that for patients prior to treatment, given the same fibrosis stage (ChenSH et al, Clin Infect Dis 2020; 70: 114-122). Adoption of the same cut-off derived from patientsprior to treatment may under-stage liver fibrosis in post-SVR patients (Pan JJ et al, HepatolCommun 2018; 2: 1320-1330). Thus, future extensive studies to establish revised cut-offs fordefining liver fibrosis in post-SVR patients through various noninvasive diagnostic modalitiessuch as FibroScan, ARFI, and FIB-4 are warranted because of the growing reluctance of patientsto undergo liver biopsy.2. Although the authors are advised to conduct a similar analysis to identify the cut-offs fordefining various stages of liver fibrosis in post-SVR patients (n = 20), the odds of success are lowgiven the small number of patients in this group. Thus, I would like to suggest the authors conduct
such analysis, attach the result in a supplementary Table, and acknowledge this limitation in the
Discussion.3. Because the authors included both pre-SVR and post-SVR patients in this study, the authorsshould provide some background knowledge about liver stiffness and liver fibrosis indexmeasurement in patients post-SVR as well as those prior to receiving treatment in the Introduction.The authors should also interpret and discuss their findings in the same context in the Discussion.4. The HCV related study subjects all had HCC and underwent surgical resection of the tumors.Were there any neoadjuvant treatments prior to surgical resection of the tumors in the studycohort? These treatments might have resulted in hepatocyte necrosis or inflammation which can
confound liver stiffness or fibrotic index measurement.
5. The pairwise statistical comparisons of the AUROCs among the four diagnostic modalitiesshould be conducted using the DeLong test to report the levels of significance.
Minor Comments:
1. To conform to the literature, please consider using "fibrosis was staged" and "fibrosis stage",instead of "fibrosis was graded" and "fibrosis grade" where applicable.2. Page 8, line 145 and 146: SVR was seen in "20" patients, non-SVR was observed in "74"patients.3. Page 8-9, line 153-154 and Page 9, line 163: please consider using "The median values" insteadof "The median META VIR scores".4. Titles of Figure 3 and Figure 4: please consider using "ROC analyses of different modalities forthe diagnosis of various stages of liver fibrosis…….".5. Please specify the case numbers in Tables 2, 3 and 4 as appropriate.6. Table 2, HCC Stage (I/II/III): 30/25/9? Please check.
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.
NoAre 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 statistics
Quality of written English
Please indicate the quality of language in the manuscript:
Needs some language corrections before being publishedDeclaration of competing interests
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