What experience has anyone had with the Signatera blood test?

@jaxfl My oncologist has my Natera blood draw coordinated with port flushes, so they do both at the same time.

My Natera results have settled in at 0.24, 0.00, 0.14, 0.17, 0.14, and 0.14. I am 22 months post RC surgery. My oncologist says the test is too new to know exactly what this means. Anyone had a similar experience and what did your oncologist say? Nothing on CT and PET scans.

@babab My surgeon and medical oncologist both essentially say the same about the meaning of the numbers. They seem to be guided by results that show detectable vs non detectable along with pet scans. My surgeon also told me that in my case there were likely not enough cancer cells to show on a cat scan. (I was upstaged to stage 3 after radical cystectomy in Jan 2024. After 4 cycles of chemo it became non detectable for about 11 months. It came back this year with a very low number 0.33 . Nothing showed on CAT scan but based on Signatera PET scan was ordered and showed uptake in pelvic nodes. 2 cycles of Padcev and Keytruda put me back to non detectable . I have PET scan and Signatera coming up after I finish cycle 6 of current treatment in next few weeks .

I do the draw the day before nivo.

Yesterday I was extremely tired and today also. Plus continuing mucus in my lungs and some faint abdominal discomfort and loser stool. So I may be experiencing low grade colitis. Wait and see how this develops. I also have cold flashes occasionally. So maybe my thyroid is fried (relatively common with ICI). My hematology gave me a script for Quest bloodwork so I will see if can do that this week or next.

@jaxfl My husband (63M) is going to start nivo tomorrow (480mg once a month for 13 months). He achieved cCR after 4 rounds of ddMVAC and pCR after his restaging biopsy. We're attempting a mash-up of the Hoosier and Retain 2/3 with bladder preservation as a goal - yes, scary, but we're also being vigilant with staggered Signatera and Tempus testing every other month.

Do you use a spreadsheet or checklist of sorts to relay side effects to your Care Team? I don't want to henpeck my Sweetheart every time he gets a sniffle. Have you found a good balance?

Congratulations! Good luck! My signatera was negative again fortunately 2025-09-26. I do not keep a spread sheet. I use a basic text file to track major IRAEs by start date and duration. I send portal messages to the care team with noticeable side effects. In my case they had me come in once so far for suspected colitis in April. They prescribed a topical steroid twice recently for the rash. Otherwise for other benign side effects they typically make supportive suggestions (OTC and rest and the like).

Consider adding akkermansia, CBM588, camu camu and antihistamines (Zyrtec, Claritin) to boost ICI. Plus request early morning infusions (chronotherapy) and stay active.

Mayo tends to get annoyed with incessant messages about anything and everything so in my case I have to reach out sparingly. Maybe your care team will be more receptive. I understand why Mayo prefers limited communication: they treat many patients obviously.

@jaxfl Thank you very much. We'll start researching the compounds that complement the efficacy of ICIs and see what the oncology team here has in their toolbox.

Most oncologists only go by phase three trials and these supplements are not there yet. But there is compelling early evidence.

I visited urgent care yesterday as Mayo told me to check in with my PCP for my symptoms. The UC PA suspected a UTI. But obviously a RC/IC will almost always show stuff you would normally not see. So that was ambiguous. Today I felt a lot better but my stool is irregular. The bloodwork from Monday also showed no significant increase in neutrophils but a moderate increase in monocytes and an inflammation marker. So my suspicion is a low grade gastrointestinal issue. My eosinophils went down to 580 something from 690. Wait and see how this plays out.

@jaxfl Hope you're feeling better soon. Immunotherapy can certainly mess with your stomach at times. I only have two months left now and I'm looking forward to ending it.