Precision Oncology Advances Poised to Transform GIST Care

Breelyn Wilky, MD, the director of Sarcoma Medical Oncology at the University of Colorado Anschutz Medical Campus in Aurora, Colorado, discusses what precision oncology advancements will most impact gastrointestinal stromal tumor (GIST) management in the next 3 to 5 years.

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0:09 | So I think we can't avoid the circulating tumor DNA concept. For other types of cancer, circulating tumor DNA has made tremendous progress. It is much more sensitive, and big clinical trials in other cancers are showing that you can use this as a tool to guide management now. [In] GIST, we are not quite there yet. Sarcomas in general tend to shed circulating tumor DNA fairly poorly compared [with] most tumors. So what that means is that you could have a patient who's progressing, you get the circulating tumor DNA test, and it is negative, or it does not have the mutations you were hoping to see. So then what do you do with that information?

0:49 | I think over the next 3 to 5 years, technology is going to continue to get better and better. We are going to continue to collect this data off of all these patients, and again, the patients most likely—at its current technology—are patients with widespread metastatic disease, high burden of disease. Those are the ones you'll tend to capture. But as we keep doing this for all of our ongoing clinical trials—which is certainly the trend—we are going to get that data. We are going to get enough patients treated in this fashion to be able to tell us what to do and how to guide therapy based off circulating tumor DNA.

1:24 | And then my goal, again, as the technology gets better, is to be able to have a patient who's had surgery, who has high-risk GIST, to be able to test them and say confidently whether or not they have residual disease. Basically this concept of MRD, or minimal residual disease, does not exist in GIST at all, because it doesn't shed well right now. But to be able to actually tell a patient, "No, you do not have circulating tumor DNA, you don't need to start imatinib [Gleecvec] for the next 3 to 5 to 7 years of your life," or to say, for somebody who's completed adjuvant therapy, to be able to follow that along the way and say, "No, you've cleared. We can stop treatment safely." I think that's what we all would love.

2:05 | Because although these drugs are well tolerated, they still impact a patient's quality of life. And, you know, patients will sometimes stop therapy, and they'll say, "You know what, I've had it." And unfortunately, I'll see patients anywhere from 6 months to a couple of years down the road where their GIST has come back, having been off imatinib therapy—and it is just heartbreaking. Being able to figure out who really needs it and who can be stopped is certainly a home run that we are looking for.