Expanding the Use of CGP in Screening and Surgery


Closing out his discussion on CGP, David Gandara, MD, looks toward future opportunities for CGP in screening patients before or after surgery.


David R. Gandara, MD: When you discuss next-generation sequencing and comprehensive genomic profiling platforms, ordinarily the first thing that comes to mind is a patient with advanced stage disease. Since 2021, and within the next few months, we have a number of studies emerging suggesting that particularly liquid biopsy—circulating tumor DNA [ctDNA], RNA, or epigenomic abnormalities—can help us either diagnose patients earlier as per screening or to help us identify which patients after surgery are at risk for recurrence. We call that MRD, or minimal residual disease. The examples I use here is we have an FDA [Food and Drug Administration] approval for an EGFR [epidermal growth factor receptor] tyrosine kinase inhibitor, osimertinib [Tagrisso], after surgery in patients with stage II and III non-small cell lung cancer who have undergone surgical resection and their cancer is found to have one of these EGFR mutations. In the future, I’m quite confident that assessing liquid biopsy after surgery will help identify which patients are at greatest risk for recurrence, and which patients might benefit the most. For example, if the patient has the surgical procedure, they had an EGFR mutation in their cancer and may be shown in blood before surgery, now it’s a month after surgery, you repeat that liquid biopsy and it’s a negative, that patient may be cured. Not sure, but they may well be. On the other hand, if you find that same EGFR mutation in their blood 4 to 6 weeks after surgery, they’re almost guaranteed to relapse. This may help us, for example, differentiate who needs these adjunct therapies and who does not. The same will apply to the recent FDA approval for immunotherapy with atezolizumab [Tecentriq]. For instance, if the ctDNA a few weeks after surgery is still positive, it’s quite likely that those patients are the ones who will benefit the most from therapy. We need to show this, those 2 trials I just mentioned, have blood collected and eventually we will know this information. If it is as I expect it will be, this will be a huge step forward in resource utilization. Which patients need the therapy, which patients do not.

Transcript edited for clarity.

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