@stageivsurvivor ,

Thanks very much for the update on where ctDNA testing stands, but I have a question regarding your comment:

"No oncologist I am aware of would use chemotherapy on the assumption of disease. "

Isn't that assumption the basis for all adjuvant post-op chemo after R0 resection?

Similarly, isn't the neoadjuvant philosophy of treating "resectable" disease when imaging (PET/CT/MRI) only shows a primary tumor based on the assumption that disease also lies elsewhere?

Also the comment:

"There are side effects with chemo and adverse events of more serious nature that can cause permanent damage to tissues and organs-hence the cautious approach when a patient says start me back on chemo without confirmatory evidence of disease."

I think there is a boundary where an oncologist can make the judgment call about an otherwise healthy patient who responded well to Folfirinox (for pre-op disease control) and also tolerated it well going back on it and being able to recognize if new side effects were becoming problematic.

In the video that I frequently cite, https://youtu.be/nd1l5-GrdVQ?si=eN53OyMbTZPHPWPb&t=192 at the 3:13 mark, Dr, Katz discusses pre-op (at diagnosis) CA19-9 levels and overall survival outcomes. It appears/implies he is using CA19-9 level as a proxy for the degree/probability of metastasis in patients considered anatomically resectable. The outcomes are notably worse for patients starting above 500 and significantly worse if above 1000. It only took about 6 weeks for my CA19-9 to go from 277 to 677, and my disease was indeed metastatic already at the 277 reading. My big concern for anyone in this situation is being able to make a quick enough response to avoid a similar fate.

Later in the video (6:52), Dr. Katz points out that of patients who had neoadjuvant therapy, approximately 80% have a recurrence after surgery, and approximately 80% of them recur within two years. It would seem assumption of disease is the winning bet more often than not.

FWIW, I have not even been able to bribe an oncologist into doing another PET scan since the one that followed my initial diagnosis/EUS. My surgeon has told me his MRIs detect smaller tumors than PET and are able to show characteristics that basically distinguish live tumor tissue from necrotic tissue, so he didn't expect sugar uptake on PET to yield any new info on me at this point, and that chest CT + Abd/Pelvic MRI would catch the first locations any new mets were likely to deposit themselves.

Thanks again,

--mm