Comparison of International Ovarian Tumor Analysis -Simple Rules (IOTA-SR) with Risk of Malignancy Index IV (RMI IV)...

Background Ovarian cancer is globally third most common cancer in women. The incidence of a symptomatic ovarian cyst in a premenopausal female being malignant is approximately 1:1000 which increases to 3:1000 at the age of 50. Objective To compare the diagnostic accuracy of International Ovarian Tumor Analysis (IOTA) simple rules and risk of malignancy index (RMI) IV scoring to differentiate between benign and malignant adnexal masses pre-operatively. Method An observational analytical study carried out to compare two cancer prediction tools among the ovarian tumor patients undergoing surgery in the Department of Obstetrics and Gynecology at Nobel Medical College, Biratnagar in the year 2024 and 2025. The diagnostic accuracy of risk of malignancy index IV and international ovarian tumor analysis SR was compared using SPSS version 16. Histopathology was the gold standard for the final diagnosis. Ethical approval was taken from institution review committee. Result Out of total 52 cases, 20 cases were classified as malignant tumors by international ovarian tumor analysis simple rules that was confirmed by histopathology in only 17 cases. 32 cases predicted by international ovarian tumor analysis SR was confirmed to be benign in 31 cases reporting Sensitivity of international ovarian tumor analysis SR to be 94.4%, specificity of 94.2%, Positive predictive value of 89.5%, negative predictive value of 96.9% and Diagnostic accuracy of 94.23%. On calculation of risk of malignancy index IV and comparing it with the histopathology report, sensitivity of 88%, specificity of 91.2%, positive predictive value of 84.2%, negative predictive value of 94% and diagnostic accuracy of 90.38%. The risk of malignancy index IV showed the highest Area Under Curve (AUC) of 0.936 followed by CA 125 of 0.783 area under curve and size of tumor demonstrated area under curve of 0.662 in the present study. International ovarian tumor analysis had better diagnostic performance than risk of malignancy index IV (chi squared test 36.45 vs 32.53). Conclusion Diagnostic performance of international ovarian tumor analysis SR is relatively better for prediction of adnexal mass in comparison to risk of malignancy index IV.