Prognostic impact of ctDNA in patients with colorectal cancer and liver metastases: Associations with progression-free and overall survival.

141 Background: Circulating tumor DNA (ctDNA) has the potential to serve as a biomarker for disease monitoring in metastatic colorectal cancer. However, the prognostic value of ctDNA in patients with liver metastases (LM) remains to be fully elucidated. This study evaluates the impact of ctDNA on recurrence-free survival (RFS) and overall survival (OS) in patients with LM. Methods: A systematic literature review was conducted with PubMed, analyzing 60 articles and including 16 unique studies. These were patients with metastatic colorectal cancer with liver metastases who underwent ctDNA testing at multiple disease time points before and after surgery. All patients underwent curative intent surgery and were R0 subsequently. Patients were stratified by ctDNA levels (positive vs negative during treatment). RFS and OS were compared between groups using R software. A random effect model was utilized. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated. Results: These nineteen studies included 2,641 patients. Overall, ctDNA positivity was associated with statistically worse RFS and OS. The pooled hazard ratio (HR) for RFS was 4.79 (95% CI, 3.57–6.42; 100%), indicating a more than fourfold increased risk of recurrence in ctDNA-positive patients. Heterogeneity across studies was moderate (I² = 56.5%, τ² = 0.1654, p