From Probability to Precision: Defining the Role of ctDNA in Breast Cancer Care

The field of circulating tumor DNA (ctDNA) for minimal residual disease (MRD) testing is experiencing rapid technological advancement, with new assays demonstrating increasing sensitivity by orders of magnitude compared to previous generations. This progress has generated significant excitement regarding its potential to revolutionize breast cancer management.

The central challenge, however, remains the lack of proven clinical utility. While ctDNA is highly promising, particularly across the neoadjuvant, adjuvant, and even metastatic settings, its current function is primarily prognostic. Standard clinical practice currently relies on a probabilistic approach, estimating a patient’s general risk of recurrence but it fails to provide the precise, individual-level risk stratification needed for personalized therapy selection.

MRD testing offers the potential to move beyond probabilistic risk to a single-patient-level assessment of both recurrence risk and response to specific therapies.

Before integrating these sensitive tests into routine practice, robust prospective clinical trials are mandatory.

Proof of clinical utility—demonstrating that ctDNA-guided interventions safely improve long-term outcomes for patients with breast cancer—is the essential prerequisite for implementing this technology.

In an interview with Targeted Oncology®, Stefania Morganti, MD, PhD, research fellow at the Dana-Farber Cancer Institute, explained the future of MRD use in patients with breast cancer, and how critical clinical trials are in this space