Leveraging ctDNA Status to Guide Treatment Strategies in Breast Cancer

The presence of circulating tumor DNA (ctDNA) during follow-up for early-stage breast cancer currently presents a management challenge. For patients who test ctDNA-positive but lack detectable metastatic disease on imaging, a truly minimal residual disease (MRD)-positive state, the standard approach is not yet established. Clinicians often resort to closer monitoring with imaging modalities such as CT and PET scans that are not routinely approved in the standard follow-up guidelines for this stage.

The primary recommendation for these patients is enrollment in clinical trials designed to test the efficacy of intensified or switched systemic therapies, with the goal of achieving MRD clearance and preventing overt recurrence.

Unfortunately, there are no currently available data or guidelines to support the safe de-escalation or cessation of treatment based on ctDNA clearance or sustained negativity in the early-stage setting. The concept is highly promising but remains hypothetical and requires validation through prospective trials.

In summary, ctDNA remains a powerful prognostic marker driving research, but its use as a directive for escalation or de-escalation of treatment is currently confined to the context of clinical trials.

In an interview with Targeted Oncology®, Stefania Morganti, MD, PhD, research fellow at the Dana-Farber Cancer Institute, spoke about the challenges faced by patients and clinicians alike in using MRD to guide treatment decisions.