Risk, Prevalence and Survival Outcomes of Ovarian Cancer in Women with Endometriosis: The ENDOCANCER Systematic Review and Meta-Analysis

Objective: Endometriosis is linked to an increased risk of epithelial ovarian cancer (EOC), especially clear cell and endometrioid subtypes. The extent and prognostic significance of this link are still not fully understood. This systematic review and meta-analysis compiles existing evidence on ovarian cancer risk, histotype distribution, and survival outcomes in women with endometriosis. Data sources: Systematic search up to August 2025. Methods of study selection: A systematic search of PubMed and Google Scholar was performed up to August 2025. Studies reporting ovarian cancer risk estimates or survival outcomes in endometriosis-associated ovarian cancer (EAOC) were included. Random-effects models generated pooled odds ratios (OR), hazard ratios (HR), and standardized incidence ratios (SIR). Risk analyses included >500 000 women; survival analyses >10 000. Tabulation, integration, and results: Sixty-seven studies met inclusion criteria. Endometriosis increased ovarian cancer risk (OR: 1.82, HR: 3.03, SIR: 1.62). EAOC patients were younger, more often premenopausal, and more frequently diagnosed with early-stage (OR: 0.29) and low-grade tumors (OR: 1.71). Clear cell and endometrioid histotypes predominated. Overall survival was significantly better in EAOC (HR: 0.48); recurrence and mortality were lower, while platinum resistance was similar. Conclusion: Endometriosis confers an increased relative but still low absolute risk of ovarian cancer. EAOC exhibits distinct clinicopathologic features and improved survival compared with non-EAOC. These findings support personalized counseling and emphasize the need for phenotype-based risk stratification and molecular markers of malignancy transformation.