Circulating blood biomarkers for minimal residual disease in hepatocellular carcinoma: A systematic review

BACKGROUND: Relapse after radical treatment remains a major concern in hepatocellular carcinoma (HCC), affecting 50-75 % of early-stage cases within 5 years. Early recurrence prediction is a clinical unmet need. Circulating blood biomarkers could provide a minimally invasive approach to detect minimal residual disease (MRD) post-intervention. Although alpha-fetoprotein has been the primary biomarker in this setting, its MRD sensitivity is limited to 50-70 %. This systematic review aims to summarize available evidence regarding the clinical validity and potential utility of emerging circulating blood biomarkers for MRD detection in HCC patients. METHODS: We searched PubMed and Embase for peer-reviewed articles and abstracts published up to 2025, and ClinicalTrials.gov for ongoing trials on circulating blood biomarkers for MRD in HCC. RESULTS: A total of 91 studies (74 with results and 17 ongoing, out of 2,386) were retrieved. We evaluated various blood biomarkers, including circulating DNA (cDNA, N = 24), circulating tumor cells (CTCs, N = 20), circulating RNA (cRNA, N = 8), and other miscellaneous (N = 22) for MRD detection in HCC. These biomarkers demonstrated encouraging results, albeit with notable heterogeneity. In particular, circulating tumor DNA (ctDNA) and CTCs stand as the most robust novel approaches, with 50-80 % sensitivity and specificity up to 94 %. Nonetheless, none of the 17 ongoing studies involve biomarker-driven intervention to prove clinical utility. CONCLUSIONS: Novel circulating blood biomarkers are mature for MRD detection in HCC. However, variability in methodologies and results highlights the need for further validation. We encourage the investigation of CTCs and/or ctDNA in interventional trials to assess clinical utility. This biomarker-driven approach may enhance adjuvant treatment effectiveness in MRD-positive cases while minimizing toxicity in MRD-negative patients.