Objective:

To find out the value of risk of malignancy index in detection of ovarian cancer and referral of adnexal masses.

Material and Method:

Patients scheduled for surgery due to adnexal mass between the dates May 2008 and August 2009 were prospectively included to the study. Risk of malignancy index (RMI) was calculated for each patient with a published formula (RMI= Ultrasonic score X menopausal status X Ca-125 (IU/ml) level). RMI > 200 was accepted as positive for malignancy and the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of RMI in detecting malignant cases were calculated.

Results:

One hundred consecutive patients of whom 80 (80%) had benign ovarian cyst, 4 (4%) had borderline lesion and 16 (16%) had invasive ovarian cancer were included to the study. Forty-five percent (9/20) of malignant cases were epithelial ovarian cancer, 20% (4/20) were borderline ovarian tumor, 30% (6/20) were non-epithelial ovarian tumor and 5% (1/20) was a metastasis from appendix. All the cases with epithelial ovarian cancer had positive RMI but only 1 of 4 borderline lesions, 2 of 6 non-epithelial ovarian cancers had positive RMI. The sensitivity of RMI was 55%, specificity was 88.7%, PPV was 55% and NPV was 88.7% for all cases. When the cancer cases other than epithelial ovarian cancers were excluded the sensitivity, specificity, PPV and NPV of RMI was 76.92%, 88.75%, 52.63% and 95.95% respectively.

Conclusions:

RMI is not adequate in detecting malignant cases in a population with high non-epithelial ovarian cancer and borderline ovarian tumor prevalence.

Keywords: Risk of malignancy index, Malignant, Benign, Ovarian cancer, Ultrasonography