A multivariate analysis of the prognostic impact of tumor burden, surgical timing and complexity after complete cytoreduction for advanced ovarian cancer

International audience; Objective: To assess the survival benefit of primary debulking surgery (PDS) compared to interval debulking surgery (IDS) after complete cytoreduction (CC-0) or cytoreduction to minimal residual disease (CC-1) in advanced ovarian cancer. Secondary objective was to evaluate the effect of tumor load and surgical complexity on patients' survival.Methods: A retrospective multicentric study was designed, including patients with IIIC-IV FIGO stage ovarian cancer who underwent PDS or IDS with CC-0 or CC-1 from January 2008 to December 2015 in four high-volume institutions. Patients were classified in three groups: PDS, IDS after 3-4 cycles of neoadjuvant chemotherapy (NACT), and IDS after 6 cycles. Disease-free survival (DFS) and overall survival (OS) were estimated. Univariable and multivariable analyses were conducted.Results: We included 549 patients, 175 (31.9%) underwent PDS, 224 (40.8%) had IDS after 3-4 cycles of NACT, and 150 (27.3%) underwent IDS after 6 cycles. Median DFS in PDS, IDS at 3-4 cycles and IDS at 6 cycles were 23.0 months (95%CI = [20.0-29.3]), 18.0 months (95%CI = [15.9-20.0]) and 17.1 months (95%CI = [15.0-20.9]), respectively; p < .001. Median OS were 84.0 months (95%CI = [68.3-111.0]), 50.7 months (95%CI = [44.6-59.5]) and 47.5 months (95%CI = [39.3-52.9]), respectively; p < .001. In multivariable analysis, high peritoneal cancer index score and NACT were negatively associated to DFS and OS. Surgical complexity and CC-1 were negatively associated to DFS.Conclusion: PDS offered a survival gain of almost three years compared to IDS in patients with minimal or no residual disease after surgery. PDS should remain the standard of care for advanced ovarian cancer.