Guiding Appropriate Cancer Treatment with Molecular Residual Disease Testing - Episode 1

Explaining Molecular Residual Disease

Jason Starr, DO, provides an overview of molecular residual disease (MRD) in the hematological and oncological treatment landscapes.

Jason Starr, DO: MRD [molecular residual disease] initially, when it rolled onto the scene, we were using it more in the hematologic space and they were referring to it as minimal residual disease, so to detect disease. After a certain treatment and as the technology has evolved, we’re now referring to it as molecular residual disease. And the way that it’s measured is a blood draw. It’s measured in the plasma, which is the beauty of molecular residual disease is that it is not invasive. And it gives you information that maybe you wouldn’t even get from doing an actual biopsy. So there’s a lot of advantages to MRD as we see it today.

There are 2 MRD assays currently and 1 of them is tumor-informed and the other is not tumor-informed. And we’ll talk maybe a little bit about the nuances about that, but essentially the tumor-informed assay reports as positive or negative, but it also gives a quantitative evaluation of the MRD, which is in mean tumor molecules. So you’ll get an absolute number. The non-tumor-informed MRD is positive or negative. And essentially, you’re measuring circulating tumor DNA and down to the actual molecules of DNA. That’s how amazing the technology has become.

I had mentioned the advantage of MRD being a blood test as opposed to tissue. Tissue, the tissue versus liquid, or blood draw, is more for detecting DNAs for treatment. We’ll talk a little bit more about that, but MRD is more for detecting disease that you can’t see radiographically. Back in the day, patients would come in after surgery and they would ask, well, one, is the disease gone, and two, is there any chance that there are cells circulating around? And what we would tell patients is, well, we don’t see anything on the scan. And we use tumor markers, which are a bit, I would say rudimentary. And so that was the best we had, but now we can tell patients with more accuracy and more refined precision, whether or not there’s disease left behind. So 1 scenario where you could envision using this is a patient with colon cancer who goes to surgery and they remove all the tumor that they see and the patient comes in the clinic and asks that question, “Is there any chance that there’s disease that’s left behind?” From a cellular standpoint, you can check this assay. And the nice thing about these tests is the specificity. So if there’s presence of molecular a residual disease, the patient is almost invariably close to 100%. Nothing’s 100%. Will have a recurrence. It’s a bit of opening Pandora’s box, but the specificity is off the charts.

This transcript has been edited for clarity.