Background: Because of conflicting reports regarding the relationship between pelvic inflammatory disease (PID) and ovarian cancer, we performed an updated meta-analysis to investigate the association between PID and the risk of this malignancy.
Methods: Embase, PubMed, and Web of Science were searched up until November 1, 2019. Hazard ratios (HRs), along with 95% confidence intervals (CIs), were calculated to analyse outcomes.
Results: We included 16 studies in this meta-analysis. PID was associated with an increased risk of ovarian cancer (HR 1.18, 95% CI 1.13 to 1.22; I2 = 41%). In subgroup analyses according to ethnicity, study design, tumour invasiveness, and type of ovarian cancer, PID was significantly associated with ovarian cancer in all subgroups. The lowest heterogeneity (I2 = 0% to 38%) was observed for associations between PID and ovarian cancer in Asian patients (HR 1.25, 95% CI 1.10 to 1.42), ovarian cancer in case-control studies (HR 1.15, 95% CI 1.08 to 1.23), invasive ovarian cancer (HR 1.25, 95% CI 1.20 to 1.30), borderline ovarian cancer (HR 1.28, 95% CI 1.19 to 1.37), and non-serous ovarian cancer (HR 1.15, 95% CI 1.07 to 1.24).
Conclusions: This updated meta-analysis demonstrated that PID is associated with an increased risk of ovarian cancer. Future large, well-designed studies are necessary to corroborate our findings.
Keywords: Inflammation; Meta-analysis; Ovarian neoplasms; Pelvic inflammatory disease; Risk factor.
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