ASCO 2022 | DYNAMIC: ctDNA guiding adjuvant chemotherapy in stage II colon cancer
Jeanne Tie, MBChB, FRACP, MD, Peter MacCallum Cancer Centre and The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia, discusses the results from the DYNAMIC trial, a study assessing whether a circulating tumor DNA (ctDNA) guided approach could reduce the use of adjuvant chemotherapy in patients with stage II colon cancer. This interview took place at the American Society of Clinical Oncology (ASCO) 2022 Annual Meeting in Chicago, IL.
Transcript (edited for clarity)
So that’s the first clinical trial, trying to demonstrate the utility of second [inaudible 00:00:10] in the early stage setting. And we started off with stage two colon cancer. That is the population that we studied for because, the clinical decision currently by colorectal oncologists in the clinic, is very difficult.
I find myself is the hardest conversation to have with the patient, whether they need chemotherapy or not, because there is no definite evidence that chemotherapy is helpful for these patients...
So that’s the first clinical trial, trying to demonstrate the utility of second [inaudible 00:00:10] in the early stage setting. And we started off with stage two colon cancer. That is the population that we studied for because, the clinical decision currently by colorectal oncologists in the clinic, is very difficult.
I find myself is the hardest conversation to have with the patient, whether they need chemotherapy or not, because there is no definite evidence that chemotherapy is helpful for these patients. Number one, because surgery alone cure more than 80% of these patients. And we have no good way of deciding which patient will need more chemotherapy and which patient can be spared chemotherapy.
So this study is aiming to demonstrate that by using ctDNA results to guide treatment, we can reduce the number of patients receiving chemotherapy, but not compromising on their recurrence risk.
So what we did was we allocate a group of patient to the ctDNA guided treatment arm, where the one patient with detectable positive ctDNA after surgery receive chemotherapy. If they don’t have detectable ctDNA, or what we call negative ctDNA, they don’t get treated.
And then the other group of patient we allocate to the control arm, where conditions essentially just managed them without the blood test, just by their conventional pathological criteria.
So the key findings from the study is that by using ctDNA results to guide therapy, we can reduce the percentage of patient needing chemotherapy from 30%, well, 28% down to 15%, almost half the number of patient needing chemotherapy.
And we also find that the outcome were almost the same between the two groups. Despite reducing a number of patient having chemotherapy, we’re not compromising on the outcome.
The other major finding we discovered was that the patient with ctDNA positive result, if they receive chemotherapy, a substantial number of them actually have a very good outcome in the long term. So suggesting that they… This is a subgroup patient who can drive a lot of benefit from chemotherapy, the ctDNA positive high risk subgroup of patient. Yeah.
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