Background: Few major studies have examined and compared the management and outcomes of patients from diagnosis to death between countries. We have established an international collaboration across Europe and South Korea to compare treatment and outcomes in Epithelial Ovarian Cancer (EOC). Methods: Patients diagnosed with EOC between January 2012 and December 2018 (age ≥18), were included for analysis. Data from medical records from five European and a single South Korean treatment centre were extracted, standardised to a common data model and analysed at each centre using a common script developed in R. Time to each progression/recurrence event (defined as time to next treatment) and overall survival have been estimated using Kaplan Meier methodology and outcomes stratified by categories of interest. Changes in the use of anti-cancer therapies over time and the incidence of BRCA mutations and incidence/timing of second breast cancers have also been examined. Results: A total cohort of 2925 patients was identified with a median age at each centre of 53 to 67 years. Advanced disease (FIGO stage III - IV) (range 57% to 84%) and high-grade serous morphology (38% to 70%) were most common at each centre. The timing of surgery (primary, interval debulking or delayed) and the proportion of patients undergoing surgery varied with stage. Patients with stage I disease where most likely to undergo surgery (range 73% to 100%) and stage IV the least (range 39% to 84%). Median overall survival for high grade serous cancers ranged from 1.9 to 4.9 years, and for the whole cohort from 2.1 to 5.5 years. Median time to next treatment at first relapse for the whole cohort ranged from 14 to 22 months. Second breast cancers were noted in 6 to 17% of patients and the majority of these occurred before the diagnosis of EOC at a median time of 96 to 118 months prior to diagnosis of EOC. Additional data on treatment pathways, BRCA status and outcomes by line of therapy for each centre will be presented. Conclusions: Preliminary analysis of results across this network suggests a variation in patient populations between sites and substantial differences in both treatments and outcomes. The establishment of a common data model and the use of a common analytic script between sites across six different countries allows for detailed exploration of the factors influencing differences in patient management and treatment outcomes in ovarian cancer patients.