Longitudinal monitoring of circulating tumor DNA to detect relapse early and predict outcome in early breast cancer.

Purpose: Detection of molecular residual disease (MRD) allows for the identification of breast cancer patients at high-risk of recurrence, with the potential that early initiation of treatment at early stages of relapse could improve patient outcomes. The Invitae Personalized Cancer Monitoring™ assay (PCM) is a newly developed next-generation sequencing approach that utilizes up to 50 patient-specific, tumor-informed DNA variants, to detect circulating tumor DNA (ctDNA). The ability of the PCM assay to detect MRD before clinical relapse was evaluated.