Background: Ovarian cancer remains one of the deadliest gynaecologic malignancies due to its late-stage diagnosis and the lack of effective early screening methods. CA-125, a serum biomarker, has long been used in clinical practice, but its diagnostic accuracy continues to be debated. Objective: This review aims to evaluate the diagnostic performance of CA-125 in detecting ovarian cancer across different clinical settings, with attention to variations based on age, ethnicity, and care context. Methods: A structured literature review was conducted using PubMed, Scopus, and Google Scholar, covering studies published between 1988 and  2025. From an initial pool of 12 studies, 6 were included based on relevance, methodological rigor, and availability of quantitative diagnostic data. Metrics such as sensitivity, specificity, PPV, NPV, and AUC were extracted and compared.Results:CA-125 demonstrated variable diagnostic performance. Sensitivity ranged from 50% to over 90%, while specificity was generally higher in hospital-based settings. One Indonesian study reported an overall accuracy of 94.5% using a 36.5 U/ml cutoff. Ethnicity affected CA-125’s predictive value, with lower PPVs observed in Asian and Black women. Longitudinal evidence showed that elevated CA-125 levels can precede clinical diagnosis by several years. However, algorithmic models like ROMA showed only marginal improvement over CA-125 alone. Conclusion: While CA-125 is a useful diagnostic tool—especially in secondary care—its limitations in primary care and across diverse populations highlight the need for context-specific interpretation. Integration with imaging, risk algorithms, and emerging biomarkers may enhance early detection and reduce false positives in ovarian cancer diagnostics.

Ovarian cancer, CA-125, tumor marker, diagnostic accuracy, sensitivity, specificity, primary care.

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