A Prospective Study Consortium for the Discovery and Validation of Early Detection Markers for Ovarian Cancer ("PREDICT") - Baseline findings for CA125.

Abstract

PURPOSE Epithelial ovarian cancer (EOC) is a lethal malignancy. CA125, the "best" available marker for detecting EOC, has insufficient sensitivity and specificity for earlier-stage disease and is not a meaningful screening tool, motivating the search for further biomarkers. Cancer biomarker discovery is enhanced by "omics" technologies. Discovery studies for EOC biomarkers should be conducted in pre-diagnosis blood samples from prospective cohorts to maximize likelihood of identifying markers that can detect disease before usual diagnosis and in earlier disease stage, while reducing methodologic biases. EXPERIMENTAL DESIGN Individual cohorts with pre-diagnosis blood samples have insufficient sample size for such studies. thus, we established "PREDICT" ("Prospective Early Detection Consortium for Ovarian Cancer")-a collaboration of nine prospective studies-to assemble a sufficient number of EOC cases with blood samples collected ≤18 months before diagnosis plus controls. The 457 cases and 1,687 controls have circulating CA125 measured using a clinical assay. RESULTS The discrimination capacity for single CA125 measurements in samples collected <6 months prior to diagnosis was high (area under the curve (AUC), PREDICT overall=0.92; range across cohorts of non-pregnant individuals=0.89-0.98), and declined with extended time between blood collection and diagnosis. Between-cohort variability in CA125 levels and predictive performance was observed. CONCLUSIONS Ongoing investigations in PREDICT are evaluating the early detection potential of tumor-associated autoantibodies and microRNAs, using CA125 as a benchmark. PREDICT is a well-characterized resource for identifying and validating detection markers for EOC that may then be used in multi-modal screening, as a complement to CA125 and combined with imaging.