Real-World Perspectives on ctDNA Applications in Breast Cancer Management: Oranus Mohammadi, MD

At a recent Institute for Value-Based Medicine® event, Oranus Mohammadi, MD, a medical oncologist and hematologist at The Oncology Institute in Los Angeles, California, discussed the evolving role of circulating tumor DNA (ctDNA) in breast cancer management. Mohammadi highlighted how ctDNA is being applied in real-world practice, from identifying actionable mutations in the metastatic setting to exploring its potential for prognosis and minimal residual disease detection in patients with earlier-stage disease. She also reflected on the importance of patient communication in genomic testing, emphasizing strategies to set expectations, address uncertainty, and reduce anxiety when biomarker results are indeterminate or not immediately actionable.

This transcript was lightly edited; captions were auto-generated.

Transcript

With increasing attention to the integration of genomics in breast cancer, how do you approach the use of ctDNA in real-world practice, particularly in terms of timing, actionability, and choosing among available assays?

Circulating tumor DNAs are basically DNA fragments of the cancer cells that can shed into the bloodstream. In this era, we have different applications for using circulating tumor DNAs to help our cancer patients.

One application is finding some mutations that we have some targeted treatments for, and we usually use these actionable mutations in metastatic settings. Also, we can use the circulating tumor DNAs for prognosis of the cancer in the future. Especially in earlier-stage breast cancer patients that got their treatments finished, we can use it as a tool to see if there is anything any molecular positivity of the circulating tumor DNAs. If we see positive MRD in our circulating tumor DNAs, it gives us an idea that maybe we have to be more aggressive with the surveillance and the monitoring of the patients.

Also, we have some data to monitor the response of our treatment using the circulating tumor DNAs, but at this era, it's mostly investigational and not actionable in this moment.

How do you help patients understand the implications of biomarker testing results, particularly when findings are uncertain or provoke anxiety?

When I order biomarker testing for a patient, before I put the order for it, I will try to talk with my patient about them, and I will try to set the expectations. When we have the result, my patient knows that what they have to expect. For example, if we're going to have germline testing, I will talk with my patient that sometimes we may have a negative result or sometimes we may have a positive result, but we may have something that is in the spectrum or in between. In this era, we don't have enough information to act on it, so my patients know what to expect in the future.

Also, if I get a result that is uncertain, I try to have a shared decision with my patient about it. I will tell them that, at this moment, we don't need to change your treatment. It's just a test that we did,so we have an idea how to check you in the future, but you don't need to worry about it at this moment.

The other way to help the patients is if they feel like there is nothing needed to be done, if there is a positive test or uncertain test, is to ask them if they want me to check it or not. Sometimes, some patients think that if we order a test that is not actionable, it's better not to check it and increase the anxiety, rather than checking it and have uncertain tests that make them more anxious.