Assessing the accuracy and applicability of the risk of malignancy index in predicting histopathological diagnoses of ovarian malignancy among patients at Saint Paul’s Hospital Millennium Medical College in Addis Ababa, Ethiopia, in 2024

BACKGROUND: Ovarian cancer is a significant global health concern, with high mortality rates and limited early detection methods. Accurate assessment of the risk of malignancy in ovarian tumors is crucial for guiding treatment decisions. OBJECTIVE: To assess the accuracy and applicability of the Risk of Malignancy Index (RMI) in predicting histopathologic diagnoses of ovarian malignancy among patients at Saint Paul's Hospital Millennium Medical College in Addis Ababa, Ethiopia, 2024. METHOD: An institution based a two-year retrospective cohort study (2022-2023) was conducted Data were collected from March to April 2024, including 230 cases through census sampling. Sensitivity and specificity analyses assessed the diagnostic performance of the Risk of Malignancy Index (RMI) against histopathology as the gold standard. Correlation analysis was done to evaluate the risk of malignancy with histopathology of ovarian tumor. Multivariate analysis used to evaluate the associated factors with Risk of malignancy index with significance set at p < 0.05. RESULT: The risk of malignancy index has strong correlation (r = 0.701) with histopathology of ovarian tumour. The sensitivity, specificity, PPV, NPV and accuracy of risk of malignancy index in the current study were 86.4%, 78%, 76%, 87.6% and 81.7% respectively. Being at premenopausal stage [AOR = 0.05; 95%CI (0.002-0.98), serum CA125 ≤ 35 [AOR = 0.002; 95%CI (0.00-0.02)] and absence of solid area are in Ultrasound [AOR = 0.03; 95%CI (0.005-0.16)] were also significantly associated with accuracy of risk of malignancy index. CONCLUSION & RECOMMENDATION: The correlation between RMI and histopathology of ovarian tumors is found to be strong. The accuracy of RMI is 81.7% and reasonably good. The menopausal status, serum level of CA-125 and presence of solid echotexture during ultrasound examination are factors significantly associated with the accuracy of risk of malignancy index. Physicians shall better use the risk of malignancy index for diagnosing the ovarian tumors.