Risk of malignancy index in the preoperative evaluation of patients with adnexal masses.

OBJECTIVE The aim of this study was to evaluate the use of a Risk of Malignancy Index (RMI) in primary evaluation of patients with adnexal masses. METHODS The RMI is based on menopausal status, ultrasonographic findings, and serum CA 125 level. A cutoff level of 200 was chosen as the threshold for referral for centralized primary surgery. This setup was evaluated by sensitivity, specificity, and positive predictive (PPV) and negative predictive (NPV) values with respect to the ability to distinguish malignant from benign pelvic masses. RESULTS The sensitivity was 70.6%, specificity 89.3%, PPV 66.1%, and NPV 91.1% for the total material. For the patients undergoing surgery the sensitivity was 70.6%, specificity 87.7%, PPV 66.1%, and NPV 89.8%. If stage I disease is considered "benign" disease, the sensitivity is 95.5%, specificity 87.9%, PPV 57.8%, and NPV 99.1%. CONCLUSIONS RMI is a simple, easily applicable method in the primary evaluation of patients with adnexal masses. It is usable as a method for selective referral of relevant patients for centralized primary surgery. The method has significant limitations in borderline ovarian tumors, stage I invasive cancers, and nonepithelial tumors. Other methods should be evaluated to increase diagnostic accuracy in these cases.