. I'm Dr Cheryl Lee. Today we'll be talking about circulating tumor DNA, or ctDNA, testing as the next step in personalized medicine for individuals with. What is ctDNA? Why is ctDNA testing relevant now, and how could it be best utilized in clinical practice when managing patients with high-risk bladder cancer?
For expert guidance on these questions, we've invited Dr Peter Black. Dr Black is a urologic oncologist at Vancouver General Hospital, a research scientist at the Vancouver Prostate Centre, and a professor in the Department of Urologic Sciences at the University of British Columbia. He received his undergraduate degree from the University of British Columbia and his medical degree from Johannes Gutenberg University in Mainz, Germany.
We can jump right into our conversation now. Over the past several years, the role of circulating tumor DNA, or ctDNA, is becoming increasingly important in oncology. We heard about it making a lot of progress in several malignancies. We see the liquid biopsy being used to diagnose or monitor cancer even to identify new targets for therapy.
I think what has really progressed quickly, though, is the second use, this monitoring that you referred to. We have commercial assays that appear to be very effective in guiding treatment. With these personalized assays, you take a piece of tissue and you sequence it to find out what mutations you expect to find in the plasma of those patients. Then you look for those specific mutations with a targeted approach, not an unbiased approach.
I think the big"event" in the last couple of years has been the one trial — IMvigor010 — in which the commercial assay was used. Patients who had ctDNA in their blood after radical cystectomy had a worse prognosis than those who didn't. This suggests that it actually is a measure of molecular residual disease, minimal residual disease.