Validity of the Risk of Malignancy Index 4 to Preoperative Evaluation of Patients with Adnexal Masses

Objective: To study the validity of the risk of malignancy index 4 in preoperative prediction for women with adnexal masses. Materials and Methods: A cross-sectional diagnostic study of women with adnexal masses admitted at Khon Kaen Hospital between 18 th May to 31 st July, 2015 for elective surgery. The sensitivity, specificity, positive predictive value and negative predictive value were calculated. Receiver operating characteristic (ROC) curve was used to evaluate the optimal cut-off point for the risk of malignancy index (RMI). Results: One hundred and sixteen women with adnexal masses were recruited (89 cases were benign and 27 cases were malignancy). The optimal cut-off point for RMI 4 in our study was 204 giving the sensitivity 82.8%, specificity 79.3%, positive predictive value 52.3%, and negative predictive value 93.2%. Using a cut-off at 450, sensitivity was 63%, specificity was 86.5%, PPV was 58.6% and NPV was 88.5%. The area under the ROC curve for the RMI 4 was 0.852. Conclusion: The RMI 4 had a validity to discriminate between benign and malignant ovarian tumors.