Extensive cytoreductive surgery in stage IV ovarian cancer may not be a justified treatment strategy
Complete macroscopic surgical cytoreduction improves survival in advanced ovarian cancer. However, our previous results suggest that the survival benefits of aggressive surgery to achieve complete macroscopic resection may vary across different subgroups. This study aimed to identify a potential poor-prognosis subgroup among patients with complete macroscopic resection. This cohort study included all patients with advanced ovarian cancer who underwent complete macroscopic resection in a public and centralized health care system setting. Two 3-year cohorts were compared: pre-implementation (cohort 1, n = 101) and post-implementation (cohort 2, n = 172) of a very high surgical proficiency setting. Overall survival was compared by relative risks (RR) stratified by stage and surgical extent. Cox regression estimated hazard ratios (HR) adjusted for relevant covariates. In patients with stage IV, median survival was 33 (cohort 2) vs 47 months (cohort 1), 7-year RR 1.01 (95 % CI 0.78 to 1.31). When extensive surgery was required in stage IV median survival was 27 (cohort 2) vs 58 months (cohort 1), 5-year RR 0.91 (95 % CI 0.81 to 1.01). By contrast, in stage III, median survival was 93 (cohort 2) vs 59 (cohort 1) months, 7-year RR 0.76 (95 % CI 0.59 to 0.98), with the greatest difference when less extensive surgery was required; Not reached vs 65 months, 7-year RR 0.62 (95 % CI, 0.43 to 0.88). Adjusted analysis confirmed improved survival in cohort 2 only after less extensive surgery, HR 0.56 (95 % CI, 0.33-0.95). The implementation of a very high surgical proficiency setting was not associated with improved survival in patients with stage IV despite complete macroscopic resection, as opposed to patients with stage III.