High mutation burden of circulating cell-free DNA in early-stage breast cancer patients is associated with a poor relapse-free survival.

Our results confirm previously observed challenges about the accuracy of liquid biopsy-based genotyping of early-stage cancers and support the parallel sequencing of tumor and cfDNA while also demonstrating how the presence of tumor-specific somatic variants and the high mutation burden in the cfDNA are both associated with the poor RFS, thus indicating the prognostic potential of liquid biopsy in the context of early-stage cancers.