Replies to Was this Decipher analysis based off your diagnostic needle biopsy sample or off of tissue taken...

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Piecing together your prostate cancer puzzle.

Prostate Cancer | Last Active: Aug 9 6:46am | Replies (13)

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@notpetecrowarmstrong

Was this Decipher analysis based off your diagnostic needle biopsy sample or off of tissue taken from radical prostatectomy?

I had a Decipher run on both and the GRID results were dramatically different; there was almost no concordance in the gene expression percentiles between the two reports. You'd think it were two different patients with two different tumors, the results were that unalike.

I discussed this with oncologists at a couple COEs and both said that Decipher is vulnerable to tumor heterogeneity. Because it's testing the phenotypic expression of mRNA and not actually doing DNA sequencing of the tumor tissue, it's apparently more prone to inconsistency than genotype-based somatic analysis. (As aside, you can get true somatic genotype analysis performed on a post-RP tumor sample, but it's a much more intensive process than running a Decipher test and most cancer centers do not typically do this for the majority of patients. I did have such analysis done by MSK after my RP because I had certain aggressive histological markers that they felt warranted the somatic testing.)

My takeaway was that this is why the GRID data is still widely regarded as being of limited clinical/therapeutic value and more for research purposes only. I would caution against drawing too confident a conclusion about your tumor characteristics from anything in this report, especially if it came from a needle biopsy.

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Replies to "Was this Decipher analysis based off your diagnostic needle biopsy sample or off of tissue taken..."

handera | @handera | Aug 4 5:04pm

@notpetecrowarmstrong

Thanks for your informative comment!

Tumor heterogeneity makes sense in that even a biopsy with multiple positive cores usually has differing Gleason scores, as in my case.

The gene expression chart is from one of my tumors taken from a Gleason 3+4 core (of which I had two), while another 5 Gleason 3+3 cores were not tested.

As I said, all this data represents additional puzzle pieces of information….maybe I was overly optimistic regarding “more than half” of the puzzle pieces being missing.😉

It seems all characterization techniques suffer from ambiguity.

In my case, serial mpMRI’s indicated that my three originally observed lesions (PIRADS 3,4 & 5), two of which were initially identified (via targeted biopsy) as Gleason 3+3, turned out to be invisible in later mpMRI scans. My urologist indicated they were most likely “just inflammation” which resolved.

Probably the most frustrating aspect to the entire PCa prognostication process is when one finds out that the “puzzle picture” has morphed (to continue the analogy).

I’m aware of the limitations of Decipher testing and analysis, as I’m also aware of mpMRI’s and biopsy pathology interpretation ambiguities.

At the end of the day, we all make a risk based decision, based on as much clinical, biomarker, somatic genomic, germline genetic and any other data we can get our hands on.

That said I believe the Decipher information is important, when combined with all the other more routinely obtained information.

I think it, at least, pushes the decision towards more confidence regarding a particular treatment or active surveillance decision.

I also believe this information will only get more useful as the research continues.