Post-Conference Perspectives: ctDNA for MRD in Lung Cancer - Episode 2
Practical advice on monitoring options for patients with NSCLC treated with definitive radiation therapy or surgery.
Strategies for Monitoring Patients with NSCLC
Mark G. Kris, MD, FASCO: So, in 2022, we have really one standard way to follow people after they've completed their therapy for stage one to three disease and that is with a CT scan. There is convention on how to do this and there are some recommendations in the guidelines, particularly the NCCN guidelines. They generally recommend, I'll talk about surgery first, a scan every six months, chest CT scan for the first three years and after that a yearly scan. For patients receiving concurrent chemotherapy and radiation, proximately the same, at least in my practice, I would recommend the same follow up, though I must say that many doctors give the scans more often for people that had simultaneous chemotherapy and radiation. There are a few nuances on this. I think the first one is that very often, radiation oncologists like to get a scan about four months after the completion of radiation, at least that's the standard at my institution. So, that's a little earlier than that six-month number that I gave before. There is some controversy on whether the contrast dye should be given and currently, there's a national shortage of contrast dye, so it's not being given at this point. So, that's another issue that that comes up. There does not appear to be a role for PET scans at this time to monitor patient and there does not appear to be a role for looking at the other areas of the body, either the brain or areas not covered by the CAT scan.
The pro of the CT is that it is easily available. It is quick and it’s our way of monitoring that we have the greatest confidence in, because that’s what we’ve used since CAT scans became widely available. The cons are that to see an abnormality on a CT scan, is the cancer would have to grow to a sufficient size, usually like a billion cancer cells. So, we’d like to think we could find it earlier than that. So, if we had patients who recurred if we found evidence of the cancers return earlier, we could then mount our response to that. And that would be, you know, that's why we're always looking for ways to be more precise in in finding the recurrence of cancer, because recurrence of cancer that's localized can still be cured. And that would be something very important to look at and to look for rather and then to try to intervene as best we can to put that patient back in a position where they can be cured.
Transcript edited for clarity