Signatera testing: Has anyone had this done?

I've had cryoablation 3 times for spots on my lungs. They have been so small that they can't even get a biopsy but assume they are cancerous from colorectal colon cancer. Dr. Buckley has done the procedures at St. Lukes in Kansas City. This procedure isn't too bad, some pain for a few days but much better than full surgery or Chemo/radiation. I hope your procedure goes well. My Signatera test went from 0 to 0 to .04 to .06 to 1.13 to 5. So far they have only found the 1 spot that was cryoablated. So I hope my next test will go back down. We will see- keeping my fingers crossed.

Diagnosed with stage 3 colon cancer a year ago. Had surgery and 12 rounds of chemo which ended in July. First round of scans and labs looked good however I just received a positive Signatera test. It went from zero to 2.0.
Need a PET scan. Oncologist said not to worry yet but how can I not? Does anyone have experience similar to this? Why would Signatera be positive and it’s not cancer all over again?

What ended up happening? Did the result go lower? Mine just came back positive. Only my second one. First was 0 now it’s 2. Getting a pet scan ordered

step by step... is a good reminder for me when I start freaking out about anything! Try to hold on, take medico recommendations and use your gut too It can tell you what seems good to do or try... keep yourself informed. I use Youtube and it is invaluable but I have worked in healthcare 15 years as a MSW/psychologist I am a foreign resident from U.S in Ecuador dx in May with Stage 3 after an emergency surgery and resection of a large tumour in the juncture of the sm/lg intestine. Keep asking quesions and remember your body has lots to tell you as well... stay strong. You have been through alot!

What is it? SIGNATERA?

I had a colon cancer mass that was completely blocking my colon, surgically removed in January 2024 -- stage IIA, clear margins, 40 lymph nodes removed, all of which tested negative. I've had no history of any cancer prior to that time. Based in part on my first Signatera evaluation, which came back 0.0, I did not receive chemo or radiation. Reversal surgery for my ostomy bag was done in May, 2024. CT scans done in March, 2024 showed no lesions in any organ in my abdomen. My second Signatera test just came back negative -- 0.0 -- yesterday, June 24, 2024. These test results coincided with my CT scan also done last week, which showed four cancerous tumors in my liver which had not been there in the March CT scan. My oncologist has ordered a biopsy this week. He was rather stunned that this had occurred ... needless to say, so am I.

@mse , There is a *slight* chance your liver tumors are independent of the colon cancer you had removed. I say this only because the Signatera test specifically looks for ctDNA cells that match those which came from your original colon tumor. If the liver tumors are independent, then their DNA would not match the older colon tumor as a "common ancestor."

In my case, Signatera was also negative (0.00 mean tumor molecules per mL of blood) at the same time my CA19-9 was 77 and MRI showed recurrent pancreas tumor at 1.3 cm. It wasn't until CA19-9 reached 279 and MRI measured the tumor at 2 cm before Signatera registered a positive ctDNA detection (0.14 MTM/mL). I was about to have the chemo port removed from my chest before this shocker came along.

My Signatera results since then have mostly been 0.00 since treatment began, with a few small deviations (0.06 and 0.04) from zero. In general, the non-zero results seem to correlate with higher CA19-9 readings, but I can't get all my providers to perform consistent enough CA19-9 and Signatera testing to truly compare them.

My understanding is that if Signatera is negative (0.00), you MIGHT have cancer; if Signatera is positive (> 0.00) you DEFINITELY have cancer DNA that matches your original tumor (from which the Signatera test was built) floating in your bloodstream. I think CA19-9 is more sensitive but less specific than Signatera, at least for solid tumors like PDAC.

Because CA19-9 is less specific (and subject to elevation or suppression from other causes), it can't be a sole determinant of cancer status or treatment effectiveness. However, if you have a long CA19-9 history and good measurement baseline over time and changes with disease status, it seems OK to give it more weight. For me, watching CA19-9 is like listening to quiet passages of music via headphones, whereas Signatera is more like listening to louder passages through a big set of speakers. The relatively low cost and availability of CA19-9 testing, coupled with my personal experience, have led me to be a huge advocate for it. (Reminder/Disclaimer: I have zero medical training.)

When I was offered Signatera testing I was told from the beginning that a negative result is not definitive-a positive result is.
My oncologist does tumor marker CA19-9 every two weeks. I understand it is less expensive than Signatera. In my case, the TM tracks the disease quite well. If TM is in normal state, that is when I “backfill” with Signatera. Either way, hopefully you will have a PET soon to confirm the liver activity. If the tumors are close together, ask about Y-90 procedure post chemo

Having colon cancer at 60 and treating with chemo, radiation and a colon resection; I have been testing with signatetera for about 18 months. At first my tests were 0 and going well for about 8 months. Then my signatera results starting going up and scans eventually showed a couple of spots on my liver and lung. After removing these and going thru full chemo again, my Signatera results have been back to zero for about 6 months. My understanding of the Signatera testing is that when the test is positive, even in vary small amounts, unfortunately the cancer is forming again. I was told they have never seen a false positive but it may take a few months to see on a scan. So you can catch cancer very early with these tests. Also, Signatera only tests the type of cancer that has currently been found and it won't detect a new type of cancer. I test with Signatera every 4-6 weeks to look for existing cancer that may redevelop and take scans every 8-12 weeks to see if any new cancers are trying to form. Stay positive and be diligent. I hope this info helps.

A measurement of zero with a Signatera test or any of the other labs doing ctDNA does not mean you do not have a recurrence/no cancer….it means nothing is detected. That can be no cancer or it can be that molecular residual disease is too small to be detected at the time the sample was tested despite the test being extremely sensitive. This is why the test is used for surveillance on a frequency of quarterly testing.