Is there any difference between genomic testing from prostate tissue vs. blood sample?

[sixmongoos]

Hi all,

My dad just had his RALP and I have heard genomic testing is useful for someone with very high-risk PCa. That being said, is there any difference between doing genomic testing now (using the post-operative prostate tissue), vs. doing it through blood sample in the future, when needed?

The urologist doesn't seem to care too much about the testing, so I think dad is being hesitant spending $$$ right now, especially after the cash outflow from the RALP. I'm just afraid that we may miss this window of opportunity, as there will be no prostate tissue to do the genomic testing in the future.

Thanks.

[Tall_Allen]

No reason to do genomic testing now. They keep prostate tissue samples for 5 years.

[Hidden in reply to Tall_Allen]

Would somatic testing be better for him? Guardant 360 or others.

[Tall_Allen in reply to Hidden]

No reason to do it now.

[Hidden in reply to Tall_Allen]

No. While both have merit I was wondering if heritable testing or somatic testing would be better when he got to the point of checking genetic makeup.

[Tall_Allen in reply to Hidden]

It would depend on why he'd be doing it. Patients are always better off focusing on the present.

[sixmongoos in reply to Tall_Allen]

Understood. Thanks TA!

[tango65]

The Decipher test is done with prostate tissue. It may help to guide therapy post RP

urotoday.com/conference-hig...

[sixmongoos in reply to tango65]

I read that the Decipher test is a prostate genomic test. Is there any difference between this vs. the Color genomic test? There seems to be multiple companies doing this and was wondering if they test different things.

[tango65 in reply to sixmongoos]

The color test is a study of the genome of the patient (germline genome). The decipher test studies the genome of the cancer (somatic genome).

The cancers and the patients usually have different genomes. For example the cancer may be BRCA positive and the patient may not have mutations in the BRCA gene.

The cancer is mutating all the time and there are mutations which are associated with rapid progression of the cancer. To decide specific treatments and to make prognosis it is necessary to study the genome of the cancer.

[timotur]

He could get a Color genomic test free as part of the Promise trial if he qualifies (confirmed prostate cancer diagnosis via tissue biopsy, prostate specific antigen (PSA) greater than 100 ng/dL and/or radiographic evidence of the disease)... or just order it and pay out of pocket (about $200).

color.com/clinicians-how-or...

urologytimes.com/view/promi...

[Hidden in reply to timotur]

I got the free one. Seemed pretty easy to get.

I just pointed them to the hospital that did my biopsy. My PSA never went over 13. No radiographic evidence of disease (I had RP).

I'm not sure what the follow-up is. I had my Color test done over 8 months ago and there hasn't been a follow-up that I recall.

[sixmongoos in reply to Hidden]

$200 seems like a good price. Do you know if we can order in Canada as well?

[Hidden in reply to sixmongoos]

It is supposedly available in Canada.

Free if you are accepted for the PROMIS RCT. (I was and I think that they accept anyone with cancer - even my brother with a Gleason 6).

Prostate Cancer Promise – In The Fight Against Prostate Cancer, Your DNA May Be The Most Powerful Tool

prostatecancerpromise.org/?...

[sixmongoos in reply to Hidden]

Thank you! We'll definitely consider it when we're back in town (out of the country atm).

I notice this test is completed through a saliva sample. Just going back to my original question - is there any difference between genomic tests using prostate tissue sample, blood sample, or saliva? Are the tests designed to serve different purposes?

[Hidden in reply to sixmongoos]

The main distinction is somatic or germline. Always know which one you're getting.

Germline is excellent to have at some time. I got mine days after my RP. I wanted to let my blood relatives know the risks, and I did NOT want to wait. I imagined a situation where I had an inherited genetic mutation and did not tell them as soon as I could, and they later found out they had PCa. I'm the type who would slather myself with blame. Weird because I never blame anyone or myself for my own personal issues.

Somatic can change over time. I am having somatic tests done every 3 or so months to watch for things that might be actionable. This was on advice from my MO (she likes the guardant 360).

This article might help explain it:

Germline and Somatic Mutations: What Is the Difference? | ONS Voice

voice.ons.org/news-and-view...

Let me know what you think of that article. I've looked at many and I thought that this one was one of the clearest ones.

[SteveTheJ]

I had the spit-in-the-test tube testing and it showed nothing. It could have been useful to my brothers had my test shown anything.