Meta-analyses reveal serum or plasma Interleukin-6 as a biomarker for malignant ovarian neoplasia

•Inter-leukin 6 (IL-6) is a proinflammatory cytokine often elevated in various neoplasms, including ovarian cancer.•A meta-analysis of continuous data was performed to further clarify the role of IL-6 in peripheral blood and peritoneal fluid of patients with various ovarian conditions.•5953 patients from 22 primary publications were included in four meta-analyses comparing IL-6 levels in healthy patients with benign and malignant ovarian conditions.•Peripheral blood IL-6 can distinguish between healthy controls, benign ovarian conditions and various ovarian neoplasms. Interleukin-6 (IL-6) has been implicated in various malignancies, including ovarian cancer. However, mixed results have been observed regarding IL-6 levels in different ovarian conditions. This meta-analysis was performed to determine IL-6 levels in the peritoneal fluid and peripheral blood among patients with various adnexal masses. Most popular English databases were searched using a predefined search formula. All studies comparing IL-6 levels in plasma, serum or peritoneal fluid of patients with benign tumors, ovarian neoplasms, and healthy controls were included based on inclusion and exclusion criteria. 5953 patients from 22 primary publications raging from 1994 to 2021 were included in the meta-analyses. A pooled IL-6 Mean Difference (MD) of 41 pg/mL for malignant tumors compared to benign ones, with a Confidence Interval (CI) between 19.8 and 62.2, a Z-score of 3.79, and statistical significance with a p = 0.0002 was observed. Pooled results for healthy versus benign ovarian conditions showed an MD of 5.45 pg/mL for serum or plasma IL-6 measurements in favor of benign tumors (CI:0.66–10.25, Z = 2.23 and p = 0.03). The analysis showed an MD for IL-6 levels of 19.59 pg/mL for healthy controls versus malignant ovarian tumors. Peritoneal fluid measurements regarding IL-6′s levels showed no significant difference between benign or malignant masses. Higher levels of plasma or serum IL-6 in ovarian neoplasia patients compared to benign conditions or healthy controls identify IL-6 as a discerning factor between benign or malignant ovarian tumors and a potential biomarker for ovarian malignancy.