Extracellular vesicle and particle-based blood test for ovarian cancer screening of average risk population: a...

Current ovarian cancer (OC) screening methods lack sufficient sensitivity to detect early-stage disease. We evaluated an immuno-PCR blood test measuring tumor-associated extracellular vesicles and particles (EVPs) in preclinical samples from average-risk women that participated in the United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS).

We conducted a blinded case-control study nested within the ultrasound and no-screening arms of UKCTOCS. Cases were women diagnosed with OC within 36 months of sample collection. Invasive epithelial cancer cases were matched 1:10 by age (±2 years) to controls without OC. Abnormal thresholds were based on previously established 98 % specificity cut-offs for the EVP-based test and a research CA125 assay. Primary outcomes were sensitivity and specificity for detecting high-grade serous carcinoma (HGSC) using samples processed within 28 h and collected up to 12 months before diagnosis.

The EVP-based test demonstrated a sensitivity of 82.9 % (95 % CI: 68.7-91.5 %) in 41 HGSC cases and specificity of 97.7 % (95 % CI: 96.7-98.5 %) in 1176 controls. CA125 sensitivity and specificity were 68.3 % (95 % CI: 53.0-80.4 %; p = 0.082) and 95.6 % (95 % CI: 94.2-96.6 %; p = 0.005), respectively. For stage I/II HGSC, EVP-based test sensitivity was 88.9 % (8/9, 95 % CI: 56.5-98.0 %), compared to 55.6 % (5/9, 95 % CI: 26.7-81.1 %) for CA125 (p = 0.149).

The EVP-based blood test exhibits high sensitivity and specificity in detecting HGSC in preclinical samples, supporting its further evaluation as a potential annual screening tool for OC in average-risk women.