Diagnostic Accuracy and Appropriate Cut Off Value of Risk of Malignancy Index in Preoperative Discrimination Between Malignant and Benign Ovarian Tumors: Prospective Cross-sectional Study

Abstract

BackgroundRisk of malignancy index (RMI) is scoring system which was introduced to differentiate between benign and malignant ovarian tumor. It incorporates CA-125, ultrasound score and menopausal status for prediction of ovarian malignancies in preoperative period. There is no universal screening method to discriminate between benign and malignant adnexal masses yet. So, this study was conducted to determine the diagnostic accuracy of RMI and determine best cut off value for RMI.MethodsProspective cross-sectional study was carried out among women with ovarian mass admitted to Gynecology ward and operated from September 1, 2019 to June 30, 2020.Data analysis was carried out using SPSS version 26. CA-125 level, menopausal status and ultrasound score were used to calculate RMI. Finally, RMI score was compared to histopathology result used as gold standard.ResultsNinity nine patients were enrolled in this study. Prevalence of benign ovarian tumors were 61.6% (61/99) and that of malignant ovarian tumors were 38.4% (38/99). The mean age for benign tumors was 30±9yrs and the mean age for malignant tumors was 50.6±10.8yrs. Among benign tumors, serous cystadenoma was the most common (36%), followed by dermoid cyst (32.9%), mucinous cyst adenoma (14.8%). The most common malignant ovarian tumor was serous cyst adenocarcinoma (63.2%), followed by mucinous cystadenocarcinoma (23.8%) and dysgerminoma (5.3%). Overall, using RMI score cut off value 220 has good sensitivity (84.2%), specificity (77%), PPV (69.5%), NPV (88.7%) and diagnostic accuracy (79.8%) for discriminating between benign and malignant ovarian tumors.ConclusionFrom this study there were high proportion of women with RMI>=220 in malignant ovarian tumors group. The study shows that there is significant role of RMI in prediction of ovarian malignancy thus helping in deciding which patients need referral to a center where gynecologic oncologists are available. It is good practice to use it in developing countries including our country because of its simplicity, safety and applicability in initial evaluations of patients with adnexal mass.

MRI Accuracy in Diagnosing Sonographically Indeterminate Masses Taking Histopathology as Standard

“…The Risk of Malignancy Index (RMI) integrates ultrasound findings, CA125 levels & menopausal status to assess pelvic masses before surgery, it has high accuracy, the RMI upper normal limit of 200 is agreed upon by experts as the best differentiating tool between benign and cancerous pelvic mass. The formula to calculate RMI = Menopause x CA125x Ultrasound Characteristics 11 . Abdominal and pelvic computed tomography (CT) is the preferred staging tool, crucial for assessing disease extension, calcification & fat.…”

Diagnostic Accuracy of Risk of Malignancy Index RMI in Patients with Adnexal Mass

“…The RMI is a grading system based on blood CA125, ultrasonographic characteristics of the ovarian mass, and menopausal state. Using the formula, we can determine RMI = Menopause x Ultrasound Characteristics x CA125 (10). The purpose of this research is to ascertain whether or not the Risk of Malignancy Index (RMI) is an effective and cost-efficient tool for making a preliminary diagnosis of malignancy in women presenting with ovarian masses prior to referring them to specialist centers for further therapy.…”