Statistical analysis
This meta-analysis’ primary outcomes are the rate of identifying tumor
and upstaging rate of the individual components encompassing a staging
surgery in clinically early-stage EOC patients. As a secondary analysis,
we will study the effect of histological type, differentiation grade,
and lymph node assessment method on the tumor and the upstaging rate.
The analysis was performed with the statistical software R version 4.0.0
(2020-04-24, R Foundation for Statistical Computing, Vienna, Austria)
with the ‘meta’ package version 4.3-0, created by G. Schwarzer,
attached. For all studies, individual proportions and 95% confidence
intervals were calculated. Because of the interstudy statistical
heterogeneity, a random-effects meta-analytical model was used to pool
the calculated proportions. Studies were weighted on their inverse
variance. The statistical heterogeneity was quantified by the
I2-statistics and the between-study variance by the tau2-statistic. The
corresponding forest plots were created to summarize the ascertained
result visually. A metaregression analysis was used to study the
association between covariates (e.g., number of resected lymph nodes)
and their relevant pooled proportions (e.g., upstaging due to lymph node
assessment). A P-value <0.05 is deemed significant.