Liquid Biopsy

[RugbyVLS]

I have a question regarding follow up testing after definitive treatment with radiation and while still on hormone therapy. As I understand it, the hormone therapy will skew both the psa test and also to some degree pet scans. Therefore, I'm wondering if a liquid biopsy that tests for circulating tumor cells might make sense.

[Tall_Allen]

You have nothing in your profile, but since you are posting on a site for advanced prostate cancer, I'm just guessing that the radiation was aimed at a metastasis. If so, as long as it was given an ablative dose, you can assume it was destroyed. If it was a bone met, it should have provided pain relief too. A liquid biopsy won't tell you anything useful about it.

[tango65]

How many bone metastases do you have. What is your PSA? Liquid bone biopsies do not have enough yield of cDNA of CTC if PSA is less than 5 , particularly if there not bone mets.

[westof]

Hmm... Here is my experience with a liquid biopsy ( I'm guessing that it may not be relevant to your question/concerns).

This is from my maiden post:

"Hi all, first post and here is my story…

2 years ago my PSA started creeping up. Met with my urologist and decided to try a liquid biopsy (Exosome) and my scores were encouraging. On a scale of 0 to 100, mine was 22 ( with a cutoff of 15.6 ) and I thought I was stable.

However, as time went on, that reassurance was short lived. My PSA started to double at an alarming rate, until it reached 28 the following year. After doing tons of research, I decided to opt for a MRI Fusion biopsy ."

Best,

AJ