Of all the gynecologic cancers, ovarian cancer has the greatest clinical challenge. It is often asymptomatic at an earlier stage and many of them present in an advanced stage for which the five-year survival rate remains low. However, the major hurdle faced by gynecologists is in diagnosing the disease early, owing to the fact that ovarian malignancies do not manifest clinically until a later stage.

As the most important prognostic factor is the quality of primary cytoreductive surgery, a high degree of suspicion and multi-diagnostic approach is required in patients with nonspecific symptoms in the high-risk age group, to detect the malignancy at its earliest. There are only few studies on classification systems to categorize ovarian mass into benign and malignant pre-operatively and to decide upon proper management and counseling of the patient.

In this study we assessed “the accuracy of International Ovarian Tumor Analysis (IOTA) simple rules with Risk Malignancy Index (RMI) to differentiate benign from malignant adnexal mass”. By evaluating the performance of each classification system, we analyzed the nature of an adnexal mass pre-operatively based on its score and hence decide upon the treatment modality. A total of 49 patients were enrolled in the study and were followed up by menopausal status, ultrasonogram and serum tumour markers.

When compared to HPE, RMI had sensitivity of 71.43% (95% CI 29.04–96.33%), Specificity was 97.62% (95% CI 87.43–99.94%), False positive rate was 2.38% (95% CI 0.06–12.57%), False negative rate was 28.57% (95% CI 3.67–70.96%), Positive predictive value was 83.33% (95% CI 35.88–99.58%), Negative predictive value was 95.35% (95% CI 84.19–99.43%) and Diagnostic accuracy was 93.88% (95% CI 83.13–98.72%) When compared to HPE, IOTA had a sensitivity of 100.00% (95% CI 2.50–100.00%), Specificity of 94.59% (95% CI 81.81–99.34%), False positive rate of 5.41% (95% CI 0.66–18.19%), False negative rate of 0.00% (95% CI - to 97.50%), Positive predictive value of 33.33% (95% CI 0.84–90.57%), Negative predictive value of 100.00% (95% CI 90.00–100.00%), and the Diagnostic accuracy was 94.74% (95% CI 82.25–99.36%).

The diagnostic accuracy of the IOTA is better than RMI in our cohort study, which is synchronous. Though the diagnostic accuracy of RMI is found to be fairly good in our study population, it has misdiagnosed 4% of patients as benign when HPE was suggestive of Malignancy which majorly questions its role as a tool for pre-operative evaluation. Subjective assessment by an experienced sonographer combined with the use of serum tumour markers currently seems to be the most effective method to preoperatively characterize ovarian tumors.