Liquid Biopsy: A Review of Non-Invasive Frontier in Cancer Diagnosis and Management

Background: Although the gold standard for diagnosis, traditional tissue biopsies have several drawbacks, such as invasiveness, sampling bias, and the inability to track tumour progression in real time. A revolutionary, non-invasive substitute that provides a dynamic and thorough understanding of a tumour’s biology from a straightforward blood sample is a liquid biopsy. The current knowledge of liquid biopsy and its clinical uses throughout the cancer care continuum is summarised in this academic review. Methods: Using databases like PubMed, Web of Science, and Scopus, we carried out an extensive literature review of peer-reviewed publications released between 2020 and 2025. The following search terms were used: “liquid biopsy,” “circulating tumour DNA,” “ctDNA,” “circulating tumour cells,” “CTCs,” “exosomes,” “cancer diagnosis,” “treatment monitoring,” and “minimal residual disease.” Articles were chosen for their clinical utility in a variety of cancer types, their relevance to technological advancements, and their emerging applications in both Western and sub-Saharan African contexts. To summarise the main conclusions, more than 20 articles, including reviews, original research, and clinical trial reports, were critically examined. Discussion: Circulating tumour cells (CTCs), circulating tumour DNA (ctDNA), and exosomes are among the essential elements of liquid biopsy that are thoroughly covered in the review. The unique information that each biomarker offers is highlighted. From molecular profiling and early cancer detection to real-time treatment monitoring and the extremely sensitive detection of minimal residual disease (MRD) and imminent relapse, we examine the diverse clinical applications. The talk also covers the special advantages and difficulties of using liquid biopsy in places with limited resources, like sub-Saharan Africa, where it may be able to get past major diagnostic obstacles. Conclusion: By facilitating a more individualised, proactive, and patient-centric approach to cancer management, liquid biopsy has the potential to completely transform oncology. Notwithstanding issues with cost and standardisation, continued research and technical developments indicate that liquid biopsies will be a vital component of cancer treatment in the future.