The Risk of Malignancy Index for Ovarian Tumours in Northeast Scotland – a Population Based Study

Abstract

Background and Aims The Scottish Intercollegiate Guidelines Network (SIGN) recommends the use of the Risk of Malignancy Index (RMI) for ovarian tumours, a scoring system based on ultrasound findings, menopausal status and CA 125 level, in the pre-operative evaluation of pelvic masses. The aim of this study was to investigate the accuracy of this as a predictive method of discriminating benign from malignant disease. Methods and Results All women who underwent oophorectomy in 2004 at Aberdeen Royal Infirmary for suspected primary ovarian pathology were evaluated. The RMI was calculated and these results were compared with the final histopathology. The sensitivity of the RMI for diagnosing malignant ovarian disease was 94% (32/34) while the specificity was 70% (76/108). Conclusions Compared to previous studies, the RMI score was highly sensitive in detecting malignant disease, although not as specific in excluding benign lesions, particularly cystadenomas and endometriomas. This can be improved by the refinement of imaging techniques as well as the use of laparoscopy in particular cases. The RMI score may also be especially valuable in directing referrals to a specialised centre.