Abstract

Liquid biopsy represents a rapidly evolving approach to cancer detection through circulating biomarkers such as circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), and exosomal RNA and proteins. Unlike traditional invasive biopsies, liquid biopsy offers a non invasive and repeatable method suitable for real-time monitoring of tumor dynamics. This review outlines the biological basis, technical methodologies, and clinical applications of liquid biopsy in early cancer detection. Recent advances in multi-cancer early detection (MCED) assays, which analyze cfDNA methylation or CTC clusters, demonstrate potential for identifying malignancy before clinical symptoms
appear, marking a paradigm shift in precision oncology. Although early-stage sensitivity remains a limitation, ongoing trials suggest that liquid biopsy will become an integral part of cancer screening, preventive medicine but also in the management of systemic therapy.