Review for 10.1186/s12876-023-02925-x (2023)

Title: Comparison of Clinicopathologic Characteristics among Patients with HBV-positive,
HCV- positive and Non-B Non-C Hepatocellular Carcinoma after Hepatectomy: A Systematic
Review and Meta-Analysis
Version: 2 Date: 19 Jun 2023
Reviewer:  Pawin Numthavaj
Reviewer's report:
Dear Editor,
I would like to congratulate the authors for a very interesting article with rigorous effort of
conducting the review of characteristic and prognosis data for non-B, non-C hepatocellular
carcinoma (nBnC-HCC). The author uses a rigorous and comprehensive review to summarize all
available evidence on these findings. Included papers are 32 studies that compared nBnC-HCC
and B or C HCC, with a total number of 26297 participants. nBnC-HCC seems to be associated
with older age, male gender, higher BMI, higher percentage of diabetes, Child-Pugh A group.
nBnC-HCC patients seems to have lower liver function tests, higher platelet counts, lower AFP,
higher tendency to have resection. Prognoses are similar among groups.
Upon reading the full manuscript, I have some of the major issues that I find that the author
could have improve their manuscript better:
1. Overall, the study has so many findings, and this translates to an overwhelming report in
numbers of mean differences, relative risks, p values (both from the actual p for each tests, and
p for heterogeneity tests), and I2 statistics in the result section. I think that the result section can
be much shortened, with less reporting of numbers of pooled mean differences for each finding,
and the author can refer to particular table or figure for the full number to aid the general reader
of the journal. Also the author did not state the unit of analysis, for example, mean difference
of age should be united as years, so the readers could understand more about the meaning of the
numbers. I suggest that the author take a closer look at this result part and rewrite it to be more
understandable to readers, particularly readers not familiar with meta-analysis results.
2. I think the PRISMA flow diagram is important in reporting any systematic review. It
emphasizes the process of the input data in the systematic review, as well as the importance
of inclusion/exclusion. Is it possible to put the PRISMA flow into the main manuscript? If the
space is of concern, some of the output forest plot can be moved into a supplement instead.
3. As all the studies are observational studies, the qualities of such studies are of utmost
importance. The authors use Newcastle-Ottawa scale to reflect such quality differences among
studies, which is proper. However, I think the readers should be able to verify the assessments as
well. In the manuscript the authors only stated the summarized NOS score in the characteristics
table. I strongly suggest that the authors put the details of the assessment of the quality of paper,
i.e., details of each dimension of quality, as a separate supplementary table.
4. In table 1 and 2 is difficult to see the result in the column RR or MD, as it is totally different
in meaning of both measurement, and which outcome is RR or MD, and which group is the
reference group.
5. In the pooling of survivals (page 11, under survival analysis subheading), I am not sure what
is the meaning of mean difference? For example, MD = 0.88 is the mean difference between
nBnC-HCC and B-HCC in what? I think the author mean hazard ratios in this section, as in the
figure it also says that it is hazard ratio.
Sincerely,
Pawin Numthavaj.