CA-125 glycovariant assays enhance diagnostic sensitivity in the detection of epithelial ovarian cancer.

Abstract

Objectives: Ovarian cancer is the deadliest gynaecologic malignancy. Due to the lack of reliable biomarkers for the detection of the early disease, most patients are diagnosed at an advanced stage resulting in poor survival. We therefore aimed at establishing novel CA-125 glycovariant assays to improve the diagnostic sensitivity and specificity of ovarian cancer.

Methods: Blood samples of 184 patients with epithelial ovarian cancers (EOC), 127 benign ovarian tumors, and 115 healthy controls were measured using GLYVAR™ Ovarian I and II assays (Uniogen) and the conventional CA-125 protein assay (CanAg CA-125 EIA, Fujirebio).

Results: The two glycovariant assays differentiated benign and malignant ovarian masses with 88.0 % sensitivity at 99 % specificity, whereas CA-125 showed 72.8 % sensitivity. The improved performance was most evident in patients with borderline or moderately elevated CA-125 concentration at diagnosis, which is a challenging group for differential diagnostics. The CA-125 glycovariant assays showed 2.5 times higher sensitivity (33.3 % with CA-125 vs. 83.3 % with the CA-125 glycovariants) at 94 % specificity. CA-125 glycovariants corrected 82.4 % of false positive results given by CA-125 concentrations with the commonly used cutoff 35 U/mL. Importantly, the CA-125 glycovariant assays detected 63.6 % of early-stage serous carcinomas from benign and healthy controls with very high 99 % specificity, while CA-125 had a sensitivity of only 45.5 %, representing a 40 % increase.

Conclusions: This is the first study describing the clinical performance of GLYVAR Ovarian I and II assays in ovarian cancer diagnostics. The results indicate that the CA-125 glycovariant assays have remarkable potential to improve ovarian cancer diagnostics.