Circulating tumor DNA (ctDNA) for molecular residual disease (MRD) blood test

[Pcnmyy]

Hello Friends, I was searching for a test (other than scans and PSA) that detects solid tumors circulating in the blood and I came across the ctDNA for molecular residual disease (MRD) blood test offered by Signatera for Colorectal Cancer. Has anyone had this test to diagnose or to detect Prostate Cancer while in remission? Is it FDA approved for Prostate Cancer? How accurate it is? Thanks.

[Darryl Partner]

These two videos might help you with some background Molecular Biomarkers for Prostate Canceryoutu.be/KogGTOqYduM(Not working as expected?)

And

Can Liquid Biopsies Replace Surgical Biopsies?

youtu.be/J04iWxvnvwM(Not working as expected?)

[Pcnmyy in reply to Darryl]

Thank you for the videos.

[Hidden]

The second guy says there’s a Foundation test and a Guardian test. No mention of a Signatera test. Suggest you coordinate with your MO to get one of those two, or coordinate with Foundation One.

[Pcnmyy in reply to Hidden]

Thank you for your reply. Well, I am aware of the two tests you mentioned. The test I am talking about detects the circulating DNA of solid tumors in blood stream. It doesn't examine genes mutations of tumors' cells as explained in Signatera website (natera.com/oncology/signate.... I also understood that the test is very effective in detecting residual disease in Colorectal Cancer patients. I am wondering if this test can be used also to detect residual disease for Prostate Cancer patients when their PSA stays undetectable for a long period of time, and somehow it can be used to conclude that the patient is cured or at least can safely start ADT vacation. I will raise these questions with my MO in my next visit in early Feb. 2022. Thanks

[Hidden in reply to Pcnmyy]

I will raise it too!

[tallguy2]

I will add to the conversation that no circulating tumor cells were detected in my blood until quite recently…last summer. The rest of the time the results were negative. So if the DNA test you refer to requires that there be CTCs you could miss out on a diagnosis that should include scans.

[Pcnmyy in reply to tallguy2]

Hello tallguy2,The test I am referring to is a blood test that detects the circulating DNA of solid tumors in blood stream. Please see the description at: (natera.com/oncology/signate....

They say it is different from the gene mutation test offered by Foundation One and is effective in detecting new and residual Colorectal Cancer.

[Hidden in reply to Pcnmyy]

I read a comment by an MO that I am familiar with that looked forward to the day that cfDNA will replace scans. I guess it just isn't here yet with prostate cancer but i intend to question that MO about it in a few days. Those other tests you cited to look enourmously accurate.

[Pcnmyy in reply to Hidden]

Thank you for the updated info. Please let us know what your MO say about this test.