Risk of malignancy index: a useful tool in primary evaluation of ovarian masses at tertiary care center in Pakistan

Background and Objective: The discrimination between benign and malignant adnexal masses is important for clinical management and surgical planning in such patients. The risk of malignancy index (RMI) is a combined parameter that is a simple, highly sensitive, and more specific scoring system based on three factors: serum cancer antigen 125 (CA-125) levels, ultrasonographic (USG) score, and menopausal status. The objective of the study is to evaluate the diagnostic efficacy of RMI for the primary evaluation of ovarian masses in females presenting at a local tertiary care hospital in Pakistan. Methods: This prospective observational study was carried out at the Gynecology outdoor clinic of Fouji Foundation Hospital, Rawalpindi, Pakistan. The study comprised 141 females admitted for surgical exploration of ovarian masses. Pre-operative USG evaluations of ovarian mass, menopausal status, and serum CA-125 levels were determined for all the patients. RMI was calculated and post-operative histopathology of resected ovarian masses was done in all the cases to confirm the diagnosis. Results: The sensitivity and specificity of CA-125 alone at a cut-off value of 35 U/ml was 67.64% and 83.17% respectively. Using a cutoff value for RMI at 200 U/ml, the specificity and sensitivity of CA-125 were 85.98% and 76.47%, respectively. The receiver operating characteristic curve revealed that RMI was a better discriminate than CA-125, ultrasound, and menopausal status alone. Conclusion: The RMI is a useful tool in the primary evaluation of ovarian masses. It can be used to differentiate between benign and malignant ovarian masses with high sensitivity and specificity. Suspected malignant patients can be referred to a gynecological oncologist for further management.