The Risk of Malignancy Index (RMI) in Diagnosis of Ovarian Malignancy

Objective : To evaluate the ability of two risk of malignancy indices (RMI) based on serum levels of CA 125, ultrasonographic score, and menopausal status to discriminate between benign and borderline or malignant ovarian tumor. Materials and Methods: A retrospective study was conducted in 209 women with pelvic masses admitted for laparotomy at Srinagarind Hospital, between January 2002 and December 2007. The sensitivity, specificity and positive predictive (PPV) and negative predictive (NPV) values of two RMI were calculated. Results: Using a cut-off level of 200 to indicate malignancy, the RMI 1 gave sensitivity of 70.6%, specificity of 83.9%, PPV of 75%, and NPV of 80.6%. The RMI 2 gave sensitivity of 80%, specificity of 78.2%, PPV of 71.6%, and NPV of 85.1%. The RMI 2 was significantly better in predicting malignancy than RMI 1. Conclusion: The RMI is able to discriminate between benign and borderline or malignant ovarian tumor.