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.