Objective: To verify the effectiveness of the Risk of Malignancy Index in the discrimination between non-invasive (benign and borderline) lesions and invasive malignant adnexal masses in daily clinical practice.
Methods: This prospective observational study was conducted in a multicentre cooperation of 11 hospitals. A total of 548 women with adnexal masses were included. Ultrasound characteristics, menopausal status and serum CA 125 level were registered preoperatively, and combined into the RMI afterwards. Final diagnosis was based on routine histopathologic examination. The decision to have patients operated by or with a gynecologic oncologist was based on the clinical impression of the gynecologist in the local hospital, based on physical examination, testing of serum samples, and ultrasound examination. This was compared with the hypothetical situation in which the RMI would have been applied as method of selection.
Results: An RMI of 200 achieved a sensitivity of 81% and specificity of 85% in the detection of ovarian cancer. Positive and negative predictive values were 48% and 96% respectively. In current practice, 64% of ovarian cancer patients were operated by a gynecologic oncologist. This percentage would have increased to 80% if the RMI with a cutoff value of 200 would have been used as method of selection.
Conclusions: In our study population, introduction of the RMI would improve the management of adnexal masses, with a higher percentage of ovarian cancer patients that are operated by a gynecologic oncologist. At the same time, referral of patients with non-invasive (benign and borderline) lesions would be reduced.