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

Abstract

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.

Keywords: Advanced epithelial ovarian cancer; Interval debulking surgery; Neoadjuvant chemotherapy; Peritoneal cancer index; Primary debulking surgery; Ultraradical surgery.