Monitoring post treatment with CtDNA

[Brysonal]

I was wondering if anybody used ctDNA tests as part of monitoring after active treatment finishes whilst hormone sensitive. I read one of its uses is:

‘Monitoring periods with no symptoms (remission of cancer). A lack of ctDNA in the bloodstream indicates that the cancer has not returned’

I am having bloods and PSA monitored monthly along with my Degerelix injection, picking up my next supply of Apalutamide and general consult with MO. This is happening tomorrow and I am hoping for a third month of undetectable PSA.

However having read about the risk of non PSA producing tumours ( I am now heavily pre treated) I am thinking of asking for CtDNA to be added for monitoring purposes. I have one from Nov 2021 pre treatment starting when bone mets were popping up everywhere but my MOs have not mentioned use for monitoring.

Is this something anyone else does?

[Farmhand]

any advice on which tests to request and where to get tested?

I have been looking for commercially available circulating tumor cell tests or mDNA or mRNA tests to evaluate treatment response and recurrence, but could only find testing for research purposes…. I think CT tests (blood) have a narrow window (17 hours?) to be received by lab?

Many tests identify Epithelial cells but not others….

Tried Cell Search, Epic (ARV-7 only available)….and some other companies but could not find appropriate company/lab.

Looking gor CTC test to quantify and identify heterogeneous pC cell population, EMT, ect.

CRCP first line ADT(Orgovyx), 8 months into Zytiga..

Has anyone had CTC test upon request?

[Brysonal]

Thank you for this. I am off on holiday for 3 weeks but see MO when I get back and want to discuss all monitoring options.

I find him amenable to suggestions but if I don’t suggest he follows the standard so is monitoring my bloods including PSA, having me weighed. Then I get a sandwich and drink before my Degarelix injection. I pick up my Apa ( after confusion every time- I’m their first Apa patient - he’d have gone Abi -) Tye clinic offer massage by cancer specialist masseurs/ reflexology etc which he signs me off to have ( and I never have time!) so all very nice but still a sausage factory at heart unless I suggest adding something different to the plan!

[Seasid in reply to Brysonal]

Here are the instructions how to inject Firmagon injections yourself during your holiday:

firmagon.com/hcp/dosing-and...

You made me laugh. I could imagine that office.

[Brysonal in reply to Seasid]

Lol- thanks for that but had it yesterday, fly Monday and will be back just before next one needed so thankfully no self injection!

[Seasid in reply to Brysonal]

than to look over the shoulder of the oncology nurse. It is clearly stated that they should fully insert a needle. They are confused because on the box it said that it is a subcutaneous injection. They are missing the point that the injection shoud be administered deep into the fet tissue.

I am getting Firmagon for more than 4 years now so I know everything about its administration.

Most important is to avoid the confusion of wanting to inject it intra muscular. One member had to stop the nurse wanting to give him Degarelix into the muscle tissue. That would be very bad. So be careful.

[Seasid in reply to Brysonal]

My oncology nurse said that nobody wants to self inject Firmagon, but it is possible.

[Seasid]

what is CEA? Is it expensive?

The Guardant360 test cost 5k A$. I belive it is not worth it if your PSA is under 5. You must have a big budget for tests.

The 68GA PSMA PET/CT scan is not too expensive here but I don't want a 13 mSv radiation.

[Purple-Bike]

I thought CEA is mainly for monitoring gastrointestinal cancer?

[Seasid]

how many MBq? What is a ligand?

[Seasid in reply to Seasid]

are you getting the CT also with the PET scan?

[Seasid]

i am still not clear with this.

I had at the start of my deases 4 PET scans every two weeks (4x 68GA PSMA PET scan 164MBq each) for reasearch purpose to monitor how the SUV max of my inumerable mets change after starting ADT.

I believed that only my last PET scan was a PET/CT.

I understand what you are saying. Maybe the last PET/CT scan had more slices?

I really don't know.