Pre-operative evaluation of ovarian mass: risk of malignancy index

To evaluate the risk of malignancy index (RMI) for pre-operative diagnosis of ovarian mass.

Observational study.

Department of Chemical Pathology and Endocrinology at Armed Forces Institute of Pathology (AFIP), Rawalpindi from January 2001 to January 2002.

The study consisted of 100 female patients consecutively admitted for surgical exploration of ovarian mass. Pre-operatively ultrasonic evaluation of ovarian mass, menopausal status and serum cancer-associated antigen 125 (CA 125) levels were carried out. Postoperatively histopathology of the resected ovarian mass was done to confirm the diagnosis. To increase the sensitivity and specificity of CA 125 for early detection of ovarian cancer, a combination of serum CA 125 with ultrasonography and menopausal status, designated as risk of malignancy index (RMI) for each patient, was calculated.

The sensitivity and specificity of CA 125 alone for the diagnosis of ovarian cancer, at cutoff level of 35 U/ml, were 83% and 82% respectively. Using RMI, at cutoff level of 125, the sensitivity was 87%, and specificity was 88%. Receiver operating characteristic (ROC) curves reveal that RMI was a better discriminant than CA 125 alone for differentiating between benign lesions and malignant ovarian tumors.

The risk of malignancy index (RMI) is a better diagnostic marker as compared to CA 125 alone because of its high specificity and sensitivity in differentiating ovarian cancer from ovarian benign lesions. It is a simple scoring system and, therefore, its application is recommended to evaluate ovarian masses in clinical practice.