What experience has anyone had with the Signatera blood test?

@babab , my mom is Stage IV urothelial carcinoma (high grade) of the upper tract (originating in the kidney / renal pelvis) with local lymph node involvement but no distant metastasis per PET scan.

We just started the third of 4-6 planned cycles of EV/Pembro, with a nephroureterectomy possibly in the treatment plan depending on response. At baseline, Natera sent two reports saying "quantity not sufficient" before inexplicably providing a third report giving her a value of 81.38 MTM / mL. This was higher than our oncologist was expecting (given lack of visible distant metastasis) but also all of this is so new, so hard to really know how to interpret.

On her second test (after her second cycle), the result was 0.00 or "Negative". We want to do cartwheels but it also seems too good to be true. Our oncologist agreed that he wanted to directly discuss with Natera, to try and gauge how much confidence he and we should have in the most recent Natera report.

The one adjustment as a result of the second report is that we are now confirmed for a consolidative nephroureterectomy after completion of just four cycles, assuming continued good news from Natera and confirmation from imaging. But it's a weird emotional place to be, to not have complete faith in a test, because our initial experience was so bumpy.

Glad to hear your MTM / mL is holding steady! You are fighting the good fight ... I hold warriors like my mom and you in so much awe.

ETA: we just got a phone call from the oncologist. Sounds like he has confidence in both results (the higher-than-expected baseline, and the second one reading 0.00), and got to see "under the hood" by speaking with a clinician at Natera directly. Even though this second report reads 0.00 and "Negative", there is a trace amount of one mutation (of the 16 tumor-informed mutations they're looking for) remaining. Natera needs to see measurable amounts of two or more mutations to read "Positive", which increases the test's specificity. So it's good we're proceeding with the third and fourth cycles in any case. But he used the term "cautiously optimistic" in the call, and agreed my mom was having a very "brisk" response to the EV/Pembro, which suggests a good outcome.

I had Stage 2, aggressive, muscle invasive bladder cancer diagnosed in April 2023. I had 12 weeks of chemo, Radical Cystectomy, and one year of immunotherapy. My Natera has stayed steady at around 0.17 molecules/ml. My oncologist wishes it was down to zero, so I continue having a Natera blood test every four months and also a CT scan. My oncologist says the Natera test is so new that oncologists are still learning how to use it. If you don't mind answering, what Natera numbers are your mother getting and how is her treatment being adjusted?

Hi @babab ,

I know you posted a while ago, but I was wondering what happened in your case?

My mother (Stage IV UTUC (cTX, cN2, cM0)) is undergoing serial molecular testing via Natera / Signatera. At the moment, it seems our oncologist is using it to help measure treatment response.

All the best,
jsbsmith