Liquid biopsy for early detection and biomarker applications in gynecological cancers: current status and future directions.

Liquid biopsy is a minimally invasive approach to early detection and biomarker assessment in gynecological cancers. This structured review synthesizes evidence on circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), exosomal non-coding RNAs, epigenetic markers (methylation and fragmentation), and multi-omics signatures across ovarian, endometrial, cervical, vulvar, and vaginal malignancies. A structured search of PubMed/MEDLINE, Embase, Scopus, Web of Science, and the Cochrane Library identified studies evaluating early detection, predictive and prognostic performance, therapy monitoring, minimal residual disease (MRD) detection, resistance mechanisms, and clinical implementation; each quantitative estimate was assigned an evidence tier reflecting study design and validation status. Multi-omics integration outperforms single-analyte approaches, with a prospective gynecological cohort reporting approximately 82% sensitivity at 97-99% specificity. ctDNA methylation and fragmentomics exceed CA125 in ovarian and endometrial cancers, and cfHPV-DNA shows high specificity in cervical disease. ctDNA dynamics are associated with PARP inhibitor response, MRD status and BRCA reversion-mediated resistance, and detect recurrence before imaging. Reported hazard ratios vary widely but differ in cohort, assay platform and sampling timepoint, and are not directly comparable. Almost all detection estimates derive from retrospective or case-control designs that overestimate performance, and none has been externally and prospectively validated; circulating HPV DNA in cervical cancer is the only marker with prospective trial-level prognostic support. No liquid biopsy assay holds an FDA or EMA indication for any gynecological cancer; pan-tumor clearances exist, but no gynecology-specific companion diagnostic, and no major oncology society recommends use outside clinical trials. Liquid biopsy complements but cannot replace tissue biopsy for diagnosis, subtyping and grading. Randomized trials controlling for lead-time bias are required to establish clinical utility.