To compare performance of risk of malignancy index 2, 3 and 4 in preoperative discrimination between benign and malignant ovarian tumours

Ovarian tumours commonly present as adnexal masses which could be benign or malignant. To predict nature of ovarian tumours preoperatively is a great challenge for the gynaecologists preoperatively because of their bizarre and atypical behaviour. The present study was done to compare performance of Risk of malignancy Index 2, 3 and 4 in preoperative discrimination between benign and malignant ovarian tumours. Methods: 175 women with ovarian tumours were included after obtaining informed written consent in the study. Risk of malignancy index 2,3 and 4 were calculated by their respective formulas using USG score, menopausal score and serum CA 125 level. Performance of these three indices were compared. Results: The sensitivity of RMI 2, RMI 3 and RMI 4 was 58.06%, 54.84% and 61.3% respectively. The specificity of RMI 2, RMI 3 and RMI 4 was 98.61%, 98.61% and 99.31% respectively. The positive predictive value and negative predictive value of RMI 4 were more than RMI 2 and RMI 3. Diagnostic accuracy of RMI 4 was 92.6% and that of RMI 2 and RMI 3 were 91.43% and 90.86% respectively. There was no significant difference in the performance of these three indices (p-.98) Conclusion: RMI is a simple, cost effective and easily applicable method to evaluate nature of ovarian tumours preoperatively. RMI 4 is slightly better than RMI 2 and RMI 3 in our study.