Strengths and limitations
The strength of this study is its methodology conducted with adherence
to the relevant PRISMA and MOOSE guidelines. We performed a rigorous
literature search within PubMed, Embase, and Cochrane Library and
assessed studies with two independent reviewers. Nevertheless, our
findings should always be interpreted within the limits of the original
studies. We attempted to control this issue by excluding high risk of
bias studies and the adoptation of strict inclusion criteria. The latter
was emphasized on the definition (i.e., adhering to guidelines) and
clear description of what comprehensive surgical staging entailed in
each study, thus ensuring comparability between studies with this
regard.
A limitation is that the Newcastle-Ottawa Scale is a tool originally
designed to assess the risk of bias in double-arm (i.e. two sample
comparative) cohort studies. However, the majority of studies within our
meta-analysis consists of single sample cohort studies. Its adaptation
here may have reduced its designed utilty as a risk of bias tool.
Furthermore, the use of published aggregate data inherent to a review
and meta-analysis, precluded a detailed subgroup analysis to a quality
level comparable to a design with individual patient data. An analysis
on the tumor positivity and staging value of the various surgical
components stratified on histology and differentiation was not reliably
possible. Also, for certain analyses only a very limited number of the
total of 23 studies (5194 cases) included in this review reported
relevant data (e.g., 1 study had data on the contralateral ovary).