Is Radiographic Aftercare Obsolete? How Testing Positive for ctDNA Can Be a Precedent for Late Relapse, Even in Low-Risk Hormone-Receptor-Positive Breast Cancer.

Current aftercare after early breast cancer overlooks recent evidence on circulating free tumor DNA (ctDNA). In this case report, we present a patient with low-risk hormone-receptor-positive breast cancer. ctDNA was first detected using a tumor-informed approach 12 months after the initial diagnosis and remained positive throughout adjuvant therapy with letrozole, while routine staging examinations showed no signs of relapse. Clinical relapse was ultimately identified nearly six years after the initial diagnosis, resulting in a lead time of four years and nine months. Current studies on ctDNA in the adjuvant setting have been conducted in high-risk cohorts and have shown a median molecular lead time of 8.9-12.4 months. Our study supports the need for large randomized clinical trials involving low-risk breast cancer patients to drive changes in clinical practice.