Chromosomal Instability in Cell-Free DNA as a Highly Specific Biomarker for Detection of Ovarian Cancer in Women with Adnexal Masses.

Chromosomal instability is a hallmark of ovarian cancer. Here, we explore copy-number alteration (CNA) profiling in cell-free DNA as a potential biomarker to detect malignancy in patients presenting with an adnexal mass. We prospectively enrolled 68 patients with an adnexal mass, of which 57 were diagnosed with invasive or borderline carcinoma and 11 with benign disease. Cell-free DNA was extracted from plasma and analyzed by low-coverage whole-genome sequencing. Patterns of chromosomal instability were detectable in cell-free DNA using 44 healthy individuals as a reference. Profiles were representative of those observed in matching tumor tissue and contained CNAs enriched in two large datasets of high-grade serous ovarian cancer (HGSOC). Quantitative measures of chromosomal instability, referred to as genome-wide -scores, were significantly higher in patients with ovarian carcinoma than in healthy individuals or patients with benign disease. Cell-free DNA testing improved malignancy detection (AUC 0.89) over serum CA-125 (AUC 0.78) or the risk of malignancy index (RMI, AUC 0.81). AUC values of cell-free DNA testing even further increased for HGSOC patients specifically (AUC 0.94). At a specificity of 99.6%, a theoretical threshold required for ovarian cancer screening, sensitivity of cell-free DNA testing was 2- to 5-fold higher compared with CA-125 and RMI testing. This is the first study evaluating the potential of cell-free DNA for the diagnosis of primary ovarian cancer using chromosomal instability as a read-out. We present a promising method to increase specificity of presurgical prediction of malignancy in patients with adnexal masses. .

©2016 American Association for Cancer Research.