Statistical Analyses

Statistical analyses were performed using R (version 3.5.1; R Foundation, Vienna, Austria). Survival analyses were conducted using Cox proportional hazards models for progression‐free survival (PFS) and overall survival (OS). Survival differences were visualized using the Kaplan‐Meier method. Multivariable survival analyses accounted for the success of primary surgical debulking, FIGO stage at the time of diagnosis, and patient age at the time of diagnosis, with the exception of the Mateescu et al data set, in which data regarding surgical debulking and patient age were not available. Within the MRC ICON7 data set, chemotherapy regimen (bevacizumab treatment vs placebo) was also accounted for in multivariable analyses where patients from both treatment arms were analyzed together. Survival differences are presented as univariable or multivariable hazard ratios (uniHR or multiHR) alongside their corresponding 95% CIs and P values. Comparisons of categorical variables were performed using the chi‐square or Fisher's exact tests as appropriate. Differences in time to disease progression from receipt of platinum were evaluated using the Mann‐Whitney U test. Adjustments for multiple testing were made using the Bonferroni correction when specified.