The role systematic lymphadenectomy plays in determining the survival outcome for advanced ovarian cancer patients: a meta- analysis.

Background: This study aims to evaluate the role systematic lymphadenectomy (SL) plays in advanced ovarian cancer (OC) patients. A meta-analysis was done to compare the progression-free survival (PFS) rates and overall survival (OS) rates between SL and unsystematic lymphadenectomy (USL). Methods: An extensive literature search from the dates of January 1, 1994, to today was performed. In total, we analyzed 15 studies [3 randomized controlled trials (RCTs) and 12 observation studies], which included 33,257 patients with advanced OC who underwent SL or USL. We compared the survival outcomes of PFS and OS between SL and USL stratified by research type, respectively. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were combined and analyzed by using the Revman 5.3 software. Results: For RCTs, SL did not improve the survival outcomes for advanced OC. Only 2 RCTs compared PFS, and 3 RCTs compared the OS rates between SL and USL. Two RCTs demonstrated that there was no difference in PFS between SL and USL (HR: 0.91; 95% CI: 0.81-1.04; P=0.16>0.05); at the same time, 3 RCTs also demonstrated that there were no difference in OS between SL and USL (HR: 0.94, 95% CI: 0.88-1.00; P=0.07>0.05). However, in observational studies, SL showed increased PFS (HR: 0.93, 95% CI: 0.92-0.95; P<0.00001) and OS (HR: 0.91, 95% CI: 0.89-0.93, P<0.00001) for advanced OC patients. The heterogeneity and publication bias in the included studies were within acceptable thresholds. Conclusions: These findings suggest the possibility that SL cannot improve survival outcomes for advanced OC patients. However, we cannot completely ignore the results of observational studies. More relevant RCTs are needed to investigate the role of SL for advanced OC patients.