Prognostic value of circulating tumor DNA in different cancer types detected by ultra-low-pass whole-genome sequencing. A systematic review and patient-level survival data meta-analysis.

Ultra-low-pass whole-genome sequencing (ULP-WGS) (≤0.5× coverage) of plasma cell-free DNA (cfDNA) has emerged as a low-cost promising tool to assess circulating tumor DNA (ctDNA) fraction. This meta-analysis aims to summarize the current findings and comprehensively investigate the prognostic value of baseline ctDNA detected by ULP-WGS in solid tumors. A systematic review was carried out by searching PubMed/MEDLINE and Scopus databases to identify eligible studies conducted between January 2014 and January 2024. Inclusion criteria comprised studies with reported overall survival (OS) and progression-free survival (PFS) outcomes across therapy-naïve patients with different solid tumors. All patients underwent baseline ULP-WGS of plasma cfDNA and were categorized as ctDNA positive (tumor fraction ≥10%) or negative (tumor fraction <10%). A one-stage meta-analysis was performed using patient-level survival data reconstructed from published articles. A Cox proportional hazards model with shared frailty was used to assess the difference in survival between arms. A total of six studies, comprising 620 patients (367 negative ctDNA and 253 positive ctDNA), were included in the OS analysis, while five studies, involving 349 patients (212 negative ctDNA and 137 positive ctDNA), were included in the PFS analysis. The meta-analysis showed that patients with baseline positive ctDNA had a significantly higher risk of death (HR = 2.60, 95% CI: 2.01-3.36) and disease progression (HR = 2.28, 95% CI: 1.71-3.05) compared to those with negative ctDNA. The presence of a positive ctDNA at baseline is associated with increased risk of death and progression in patients with same stage cancer.