Eligibility criteria and study selection
All comparative studies that assess clinical outcomes and prognostic value of sysLN in patients with ovarian cancer were considered eligible. Studies were included regardless of disease stage, chemotherapy (adjuvant or neoadjuvant), or control group (no lymphadenectomy [noLND] or selective lymphadenectomy [selLND]). Exclusion criteria included non-comparative studies, review articles, conference papers, and case series. Neither language nor sample size were considered during study selection.
Retrieved studies were screened through 3 stages by two independent reviewers. The first stage involves screening of titles for irrelevance. Abstracts of remaining articles were screened for eligibility. Eventually, full texts of selected abstracts were reviewed for final inclusion. Overall survival (OS) and progress free survival (PFS) present our primary outcomes. Secondary outcomes include:  (l) Intraoperative outcomes: operative time, and intraoperative complications. (II) postoperative outcomes: hospital stay, postoperative complications.