Introduction/Background Although current literature shows a clear advantage of complete primary cytoreduction in treatment of ovarian cancer, oncological outcome overall remains unsatisfactory. Proven prognostic factors for selection of the appropriate individual treatment strategy are necessary.

Methodology In our 15-year retrospective study, a detailed analysis was conducted concerning postoperative Clavien-Dindo categorized complications and long-term outcome in a single-center all-comer cohort of patients (n=309, 01/2006–03/2019) with FIGO III or IV ovarian cancer after primary maximum effort cytoreductive surgery. The impact of particular surgical steps using the Surgical Complexity Score (SCS) was studied.

Results Age, surgical complexity and diabetes significantly increased the risk for major complications (SCS per point, OR 1.210, p=0.001) or death within 30 days after surgery (age per year, OR 1.068, p=0.048; SCS per point, OR 1.274, p=0.006; diabetes, OR 6.048, p=0.026) in a multivariate logistic regression analysis. Considering the individual surgical interventions, abdominal peritoneum stripping (major complications, OR 2.466, p=0.015; death, OR 4.558, p=0.026) and large bowel resection (major complications, OR 4.309, p=0.002; death, OR 4.416, p=0.028) were significantly associated with increased risk. Surgeries with a high complexity, age and small bowel resections had an unfavorable impact on long-term survival. Multivariate Cox regression analysis identified age (DFS, HR per year 1.032, p<0.001; OS, HR per year 1.036, p<0.001), SCS (DFS, HR intermediate vs. high 0.608, p<0.002; OS, HR intermediate vs. High 0.660, p=0.013) and, particularly, small bowel resection (DFS, HR 1.624, p=0.011; OS, HR 1.953, p=0.001) as significant prognostic factors. A detailed analysis showed best survival for patients without small bowel resection and complete tumor removal. Limitation: Information on response to chemotherapy was not available for all patients yet.

Conclusion Tumor spread should initially be considered for treatment stratification, particularly with respect to age, in order to reduce morbidity and increase long term survival, even if complete tumor resection appears technically feasible.

Disclosures The authors have no potential conflict of interest to report.