Thoughts and experiences with Guardan... - Advanced Prostate...

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Thoughts and experiences with Guardant 360 somatic testing

SeosamhM profile image
17 Replies

Happy summer, folks. This is a posting inspired by smurtaw's recent post on Guardant 360 testing (see: healthunlocked.com/advanced.... Apparently tested folks are not only getting cancer biomarker indications from this test, but also a "Tumor Mutational Burden (TMB)" score.

I really only know Guardant 360 by rumor and research. It is (per the manufacturer literature) a test that is "...FDA-approved for complete genomic testing across all solid cancers, providing doctors guideline-complete genomic results in 7 days from a simple blood draw to inform treatment decisions." So...

Does anyone have any thoughts or experiences with Guardant 360 (or its competitors, if they exist) that they'd like to share? While I categorically discard the hype of "complete genomic testing" (a moving target, for certain!), it does seem like this test fits into standard of care...somehow, somewhen...

Thanks! - Joe M.

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SeosamhM
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Tall_Allen profile image
Tall_Allen

If one has lots of big metastases shedding , it's great. Uneven results from smaller metastases.

SeosamhM profile image
SeosamhM in reply to Tall_Allen

Thanks. It makes sense that free-floating tumor "trash" density is critical to detection. See smurtaw's reply about his MO use as a screening tool - it seems to be an interesting application, but certainly not one currently use in our SOC.

Tall_Allen profile image
Tall_Allen in reply to SeosamhM

That would be a very expensive screening tool.

SeosamhM profile image
SeosamhM in reply to Tall_Allen

Yah - just found that out doing some Medicare research for another poster..... the test retails $5K...

tango65 profile image
tango65

The problem is to get enough genetic material from the tumor in the blood sample. It may work in people with multiple metastases and a PSA greater than 5 or according to other studies greater than 10. The larger the tumor load and the PSA the higher the chances of getting a good study.

pubmed.ncbi.nlm.nih.gov/352...

SeosamhM profile image
SeosamhM in reply to tango65

Thanks, Tango - great resource.

Herman_PSA_OK profile image
Herman_PSA_OK

I just got my results back for my Guardant-360 blood test and it detected an alteration biomakers PIK3CA V448_L452del (1.1% of cfDNA). My appt. with my medical oncologist is next week. What the heck does that mean and how does it relate to my PCa? The report indicated Alpelisib as an associated FDA-approved in other indication. In other words, not FDA approved for prostate cancer. It also provided information for a local near me clinical trial availability for this biomarker defect. Any comments or suggestions would be appreciated.

Sleepyeye1911 profile image
Sleepyeye1911

The Gardant 360 test can help considerably.Because of this, I was put on Keytruda. Wonder

Drug for some patients.

noahware profile image
noahware

I was also wondering, after looking at the Guardant website, when the second of these two panels might be indicated or beneficial:

"A Guardant360 CDx report contains both professional services, which includes 74 genes, in addition to the FDA-approved report, which includes 55 genes."

"Guardant360 TissueNext is an analytically validated tissue comprehensive genomic profiling panel that includes TMB, MSI status, and PD-L1 IHC, if ordered. A Guardant360 TissueNext report includes 84 genes."

Even though both list a total of 84 genes for Point Mutations and Deletion Variants, for example, the TissueNext report lists CHEK2 while the CDx report does not.

SeosamhM profile image
SeosamhM

Hmmm. Why not, right? Another tool in the chest, yah?

SeosamhM profile image
SeosamhM

Well, if insurance isn't balking - I'm also a sucker for data. I will look into it. You would think the Guardant manufacturer would be pushing for this if only to move it into routine screening status and more $.

dhccpa profile image
dhccpa

Does Medicare pay for the test? If so, under what conditions?

SeosamhM profile image
SeosamhM in reply to dhccpa

Yes, it looks like some "liquid biopsy" tests were approved in 2020, including Guardant. The key language is here:

cms.gov/medicare-coverage-d...

The conditions seem straight forward: Patient has been diagnosed with a recurrent, relapsed, refractory, metastatic, or advanced solid tumor that did not originate from the central nervous system.

While I am still on private health insurance, I always ask my LPN case manager and office staff about these things!

dhccpa profile image
dhccpa in reply to SeosamhM

Thanks! I'll follow up on that.

SeosamhM profile image
SeosamhM in reply to dhccpa

Dunno if link appeared correctly: cms.gov/medicare-coverage-d...

dhccpa profile image
dhccpa in reply to SeosamhM

Thanks

noahware profile image
noahware

I frankly don't know a thing about any genetic testing costs, or how insurance might or might not cover different tests. I plan to bring it up at my next MO appt... but sounds like a good topic for a new thread!

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