What experience has anyone had with the Signatera blood test?

Thank you & so sorry for delayed response . I did chemo after RC.

The rash escalated to my sides, chest and back. I received a topical steroid. It is receding. Very uncomfortable. The PA does concur it is encouraging from an efficacy perspective.

The rash is more pronounced and the itch is noticeable. So far I am managing it with Claritin and Benadyrl. Interestingly, the forearm rash is down but the itch elsewhere is up. The good news is that rash is indicative of treatment efficacy. https://academic.oup.com/oncolo/article/28/12/1072/7191799

Interesting that GC is still very common. I have an annoying rash all over my body in a lot of spots but especially the back of my lower arms now. So I finally joined the ICI rash club.

Curious did you do chemo before or after your RC? Mine was before but same chemo cocktail as yours. I've been on Opdivo for 8 months now post surgery (headed for 12). It's easy to why scans are done so frequently. I had a PET scan in June. I wish you all the best!!

@ Holly: excellent!

@ ronzee50: excellent! I still have old tests showing as pending and canceled from 2024-12. Good thing you called.

@ 141emp: It is good that signatera helped early detection and that EVP is working. It is interesting you did not receive adjuvant preventative nivo based on checkmate 274 after adjuvant GC (and that they opted for GC instead of DDMVAC). Did you draw a signatera after RC and before starting GC? Hopefully you can finish a few EVP cycles and then switch to just maintenance pembro for two years. Signatera before RC should become standard of care: sadly it is not yet. You could potentially boost pembro with akkermansia, CBM588, camu camu, Claritin/Zyrtec, morning infusions (chronotherapy), exercise and intermittent fasting.

I have high grade muscle invasive bladder cancer initially thought to be stage 2 after a turbt at a local community based hospital. My new doctors strongly advocate the use of Signatera. (I’m now at a major NY city cancer teaching and research hospital ) My initial Signatera result was 18.0 prior to radical cystectomy surgery to and was restaged post radical cystectomy to stage 3 advanced cancer. I went to non dectectable after 4 cycles of gemcitibine and cisplatin. It stayed that way for 11 months and became detectable again with a number of 0.33. A pet scan showed uptake in one concerning uptake in one lymph node and I was put on padcev and keytruda. I am back to non detectable after 2 cycles of the new drug. I should also say that in no time since initial diagnosis in 2023 did a CT scan show that the cancer had spread outside my bladder. The spread wasn’t confirmed until the pathology post radical cystectomy.
So I would have to say that Signatera is giving my doctors early warning that there is a problem and has been a great tool to guide treatment. It was devastating to hear that the cancer came back this year but the early warning , confirmed with a pet scan gave us a heads start on treatment that might have taken months to show on a CT scan.

That's such great news @jaxfl. We've completed three ctDNA draws and all have come back clean. Let's keep the party rolling.

Finally got my results from Natera after three months of waiting. The first samples from Mayo surgery in May 2025 were not useable. They needed samples from my TURBT in late 2024. The good news was the results were negative. Natera’s patient portal sucks. It still shows they are waiting for tissue. It does not show any results. After two months of asking why the portal has not been updated, they gave me a phone number to call. If they would have done that two months ago, I would not have to make a bunch of phone calls to find out the status of my test.

My 8/27 Signatera was negative again fortunately. My 8/28 CT scan showed ground glass, mucus plugging and a few nodules < 4mm. My oncologist and Cancer Commons think this is another IRAE. Likely related to my left side sinusitis symptoms. So this negative Signatera highly likely corroborates this. My 8/27 MRI was clear and even showed the liver iron deposit (likely cause by 2X 1000MG iron IV before and during DDMVAC) resolved as did the adrenal glad atrophy (another IRAE).