Peroperative extent of peritoneal metastases affects the surgical outcome and survival in advanced ovarian cancer.

Objective: Determining whether cytoreductive surgery (CRS) is feasible in patients with advanced ovarian cancer and whether extensive surgery is justified is challenging. Accurate patient selection for CRS based on pre- and peroperative parameters will be valuable. The aim of this study is to assess the association between the extent of peritoneal metastases as determined during surgery and completeness of interval CRS and survival.

Methods: This single-center observational cohort study included consecutive patients with newly diagnosed stage III-IV epithelial ovarian cancer who received neoadjuvant chemotherapy and underwent interval CRS. The 7 Region Count (7RC) was recorded during surgical exploration to systematically quantify the extent of peritoneal metastases. Logistic regression analysis was performed to predict surgical outcomes, and Cox regression analysis was done for survival outcomes.

Results: A total of 316 patients were included for analyses. The median 7RC was 4 (interquartile range: 2-6). Complete CRS was performed in 58%, optimal CRS in 30%, and incomplete CRS in 12% of patients. A higher 7RC was independently associated with lower odds of complete or optimal CRS in multivariable analysis (odds ratio [OR] = 0.45, 95% confidence interval [CI]: 0.33-0.63, p < 0.001). Similarly, a higher 7RC was independently associated with worse progression-free survival (hazard ratio [HR] = 1.17, 95% CI 1.08-1.26, p < 0.001) and overall survival (HR = 1.14, 95% CI 1.04-1.25, p = 0.007).

Conclusion: The extent of peritoneal metastases, as expressed by the 7RC during surgery, is an independent predictor for completeness of CRS and has independent prognostic value for progression-free survival and overall survival in addition to completeness of CRS.