A reflex testing protocol using two multivariate index assays improves the risk assessment for ovarian cancer in patients with an adnexal mass.

Abstract

Patients with adnexal masses suspicious for malignancy benefit from referral to oncology specialists during presurgical assessment of the mass. OVA1 is a multivariate assay using a five-biomarker panel which offers high overall and early-stage sensitivity. However, OVA1 has a high false-positive rate for benign masses. Overa, a second-generation multivariate index assay was developed to reduce the false-positive rate. The aim of the present study was to use Overa as a reflex for OVA1 and increase specificity. OVA1 cut-off scores were established to place patients into three categories: low, intermediate, and high cancer risk. Samples with intermediate-risk OVA1 scores were reflexed to the Overa and defined as high or low risk. This protocol was tested with 1035 prospectively collected serum samples and validated with an independent prospectively collected sample set (N=207). Thirty-five per cent (359) of samples had intermediate OVA1 scores. Reflexing these to Overa eliminated 58% of the false-positives and improved the overall specificity from 50% to 72%. This finding was confirmed in the independent dataset, in which the specificity increased from 56% to 73%. Reflexing samples with intermediate OVA1 scores significantly decreases the false-positive rate, thereby reducing unnecessary surgical referrals.