Liquid Biopsy: A Non-Invasive Approach to Tumour Profiling Metastasis is responsible for 90% of cancer-related deaths, yet most treatments focus on primary disease. Despite its critical role in cancer progression, metastasis remains largely unaddressed therapeutically, with limited targeted interventions and no effective prevention strategies. Understanding metastatic spread is essential for developing early interventions.
Liquid biopsy is a non-invasive method for real-time tumour monitoring. Compared to tissue biopsy, it allows serial sampling for disease monitoring and treatment decisions. In metastatic cancer, liquid biopsy is crucial for tracking clonal evolution and resistance mechanisms over time. Beyond metastasis, it holds promise for early cancer detection, minimal residual disease (MRD) monitoring, and refining treatment strategies to reduce relapse risk. Circulating tumour DNA (ctDNA), a key component of liquid biopsy, has rapidly emerged as a non-invasive biomarker for cancer diagnosis, monitoring, and treatment guidance. It provides real-time insights into tumour mutations, supporting personalised treatment strategies. Despite its promise and the ease of sample preparation and scalability, ctDNA is yet to reach its full potential in cancer care.
Current use of ctDNA in Clinical Applications
Due to its ease of collection and scalability of analysis, ctDNA has become the predominant analyte in liquid biopsies in clinical practice. Next-generation sequencing (NGS) technologies, traditionally applied to tumour tissue, can also analyse ctDNA from a simple blood draw, facilitating the identification of oncogenic drivers and resistance mechanisms while enabling repeated monitoring.
Currently ctDNA is used in two key applications: real-time disease monitoring and treatment guidance. In monitoring, ctDNA enables tracking of treatment response and emerging resistance mutations. It is also used for MRD detection after surgical resection, helping tailor adjuvant therapies and identify patients at risk of recurrence particularly in lung and colorectal cancer.
