Circulating tumor DNA as a prognostic indicator of colorectal cancer recurrence—a systematic review and meta-analysis

PURPOSE: Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. After resection, patients need extensive follow-up to detect asymptomatic recurrences as early as possible to obtain optimal treatment. This study evaluated the prognostic value of circulating tumor DNA (ctDNA) for CRC recurrence. METHODS: Two investigators independently conducted a systematic literature search of peer-reviewed studies that investigated the prognostic value of ctDNA in CRC. Fixed effects or random effects models were applied for all analyses based on the assessment of heterogeneity. RESULTS: A total of 189 studies were initially retrieved from all databases; ultimately, eight studies with 879 CRC patients were included in this analysis. The pooled median recurrence-free survival was 11.36 months for ctDNA-positive patients. Meta-analysis of hazard ratio (HR) suggested that postoperative ctDNA-positive patients were more likely to experience cancer recurrence than ctDNA-negative patients (pooled HR: 5.41; 95% confidence interval (CI): 2.37–8.45). CONCLUSIONS: Successive monitoring of ctDNA status and follow-up with postoperative computed tomography (CT)/magnetic resonance imaging (MRI) are useful tools to detect early recurrence in postoperative ctDNA-positive patients.