Impact of Ovarian Cancer Surgery Volume on Overall and Progression-Free Survival: A Population-Based Retrospective National French Study.

BACKGROUND:Data are limited on the relationship between ovarian cancer surgery volume and outcomes in France. METHODS:For this retrospective, population-based study, patients with ovarian cancer that was diagnosed between January 1, 2012 and December 31, 2016 were identified from the French National Health Data System (SNDS). Hospitals were classified in function of their ovarian cancer surgery volume. Patient, tumor, hospital, and hospital stay characteristics also were evaluated. The hospital procedure volume effect on 5-year overall survival (OS) and recurrence-free survival (RFS) was determined with Cox-proportional hazards models. RESULTS:This study included 8429 patients and 53.4% underwent cytoreductive surgery in hospitals with procedure volume < 20 cases/year. The 5-year OS rates were 63% and 60% in hospitals with procedure volume ≥ 20 and < 20 cases/year (p = 0.02). In multivariate analysis, OS and RFS were significantly increased when surgery was performed in hospitals doing ≥ 20 surgeries/year (vs. < 20) (hazard ratio HR = 1.18, 95% CI = 1.08-1.29 and HR = 1.10, 95% CI = 1.03-1.17). In the volume subgroup analysis, a difference was observed mainly between hospitals with < 10 surgeries/year and the other hospitals (HR = 1.27, 95% CI = 1.14-1.41 and HR = 1.14, 95% CI = 1.05-1.23). The patients' age and comorbidities, tumor stage, and hospital stay (duration, first cytoreduction surgery) were associated with OS. CONCLUSIONS:Ovarian cancer surgery volume ≥ 20 cases/year was significantly associated with improved OS and RFS but only with a limited clinical benefit. The biggest differences in OS and RFS were observed between hospitals with procedure volume < 10 cases/year and all the other hospitals.