Implementation of ctDNA in Breast Cancer / ctDNA 08/28/2026

Ep. 2: Challenges of ctDNA Testing in Breast Cancer

Indian male oncologist in white lab coat, smiling for medical professional image, representing cancer research and treatment, on OncUpdates website. Matthew Kurian, MD Professional portrait of a smiling man in a dark suit and striped tie, suitable for medical or healthcare-related content on OncUpdates. Wassim McHayleh, MD 1. Smiling female healthcare professional in white coat, headshot portrait, oncology specialist in medical setting for cancer treatment and research. Eleonora Teplinsky, MD Smiling man with beard wearing a white shirt, professional headshot, suitable for oncology or cancer research content, emphasizing healthcare and medical expertise. Rahul Gosain, MD, MBA Oncologist smiling in white coat, highlighting cancer research and treatment expertise, with a bow tie, in a bright medical setting. Rohit Gosain, MD

Key Points

  • In breast cancer, circulating tumor DNA (ctDNA) testing may indicate risk of recurrence and inform the frequency of scanning, but ctDNA findings alone cannot prompt therapeutic interventions.
  • Currently ctDNA has some utility as a confirmatory tool in patients with breast cancer who have inconclusive imaging or other uncertain evidence of recurrence.

Challenges in Using ctDNA Testing in Breast Cancer

During a panel discussion on ctDNA in breast cancer on the Oncology Brothers podcast, Eleonora Teplinsky, MD, of Valley-Mount Sinai Comprehensive Cancer Care, and Wassim McHayleh, MD, of AdventHealth, spoke on the challenges facing ctDNA testing in breast cancer today.

Data have shown ctDNA is prognostic in breast cancer, but it has not been established as a predictive marker. Although ctDNA tests can be sensitive for detecting molecular disease, trials have not yet established that treatment decisions based on ctDNA results improve outcomes for patients. Earlier trials sought to determine if ctDNA negativity could be a surrogate for pathologic complete response in triple-negative breast cancer, but were unsuccessful, Dr. McHayleh said. 

Despite these challenges, more patients are aware of and requesting ctDNA testing, so oncologists need to be prepared to discuss the current data on ctDNA and interpret testing results, Dr. McHayleh said.

While specific clinical actions to take based on ctDNA testing have not been determined, it can still be a helpful tool for characterizing a patient’s disease and monitoring response and remission. Testing can be performed in between regular imaging as additional monitoring for potential recurrences. Furthermore, ctDNA testing can be valuable as a confirmatory tool for patients with inconclusive imaging or uncertain evidence of recurrence, Dr. Teplinsky said.

Although ctDNA results can inform the frequency of scanning and the risk of recurrence, ctDNA positivity alone is not an evidence-backed basis for intervening. As a result, patients who request ctDNA testing and see a positive result may be anxious that they are not starting additional therapy. Conversely, patients who have negative ctDNA may question the necessity of continuing adjuvant therapy. Overall, oncologists need to be clear with patients about what ctDNA can accomplish currently and what decisions can be informed by test results, the doctors said.