Performance of the American College of Obstetricians and Gynecologists' ovarian tumor referral guidelines with a multivariate index assay

Objective: The American College of Obstetricians and Gynecologists (the College) published referral guidelines for women with a pelvic mass that incorporate CA 125. A new multivariate index assay assesses the malignant risk of ovarian tumors before surgery. Our objective was to estimate the performance of the College guidelines with this new multivariate index assay. Methods: This prospective, multi-institutional trial included 27 primary care and specialty sites throughout the United States. The College guidelines were evaluated in women scheduled for surgery for an ovarian mass. Clinical criteria and blood for biomarkers were collected before surgery. A standard CA 125-II assay was used and the value applied to the multivariate index assay algorithm and the CA 125 analysis. Study results were correlated with surgical pathology. Results: Of the 590 women enrolled with ovarian mass on pelvic imaging, 516 were evaluable. There were 161 malignancies (45 premenopausal and 116 postmenopausal). The College referral criteria had a modest sensitivity in detecting malignancy. Replacing CA 125 with the multivariate index assay increased the sensitivity (77-94%) and negative predictive value (87-93%) while decreasing specificity (68-35%) and positive predictive value (52-40%). Similar trends were noted for premenopausal women and early-stage disease. Conclusion: Replacing CA 125 with the multivariate index assay improves the sensitivity and negative predictive value of the College referral guidelines while decreasing specificity and positive predictive value. The high sensitivity is maintained in premenopausal women and early-stage disease.