Signatera Numbers are sky high and I'm terrified

Posted by kat77 @kat77, Oct 21, 2023

Hi All-

Stage 4 metastatic colon cancer. Recurred in my skull and in bone mets in my spine, pelvis and femur, diagnosed in Sept 2022. Had a craniotomy, radiation in skull and lower back, did 12 rounds of the standard FolFox/Oxil. Everything shrank and and continued to shrink.

I stopped chemo June 1 and due to some pretty serious communication problems with my oncologist, I left him and started seeing another. I was off any chemo from June 1 to Aug 25, when I began taking 4000mg of Xeloda per day, 14 days on, 7 days off. On Sept 15 I started Avastin once every three weeks. (I had to delay the Avastin because I had to have non-cancer related surgery on my spine and needed the time to heal before taking Avastin.)

My old oncologist had been doing Signatera tests on me periodically without my knowledge while I was doing chemo, and then sent someone to my home to take blood. He never shared the test results with me even though I asked. My new oncologist did the first Signatera blood draw during my 2nd Avastin dose on Oct 6. I just saw those results (and the results of the previous three tests) today.

In April, my number was 3. In July, it was 58. In mid-Aug, a week before I began Xeloda, it had jumped to 219. And my Oct 6 number, after doing two rounds of Xeloda and one round of Avastin, the number had jumped to 273. Needless to say I am a basket case.

We had done a PET scan in June which showed further shrinking, and I had an MRI of my pelvis in August which showed no further growth. My last CEA test was July 19 and it was 0.4. I am flabbergasted that my Signatera numbers have jumped so high so quickly and I don't know what to think. My new oncologist responded to me right away and wants to do a new PET/CT to see what's going on.

Has anyone ever seen Signatera numbers jump so high, so quickly? I'm guessing this means the Xeloda/Avastin aren't working, and I'm not sure where that leaves me with treatment or if I have any hope at all of bringing this back down and keeping it in check for at least a couple years. I thought I was doing so well and now it's looking like I'll be lucky to see another year. And I cannot stop thinking about it.

If anyone has had any experience with the Signatera numbers, or has not seen progress with Xeloda, curious what your next plan of action was.

Thanks for listening.

KT

Interested in more discussions like this? Go to the Colorectal Cancer Support Group.

@mvbny

Hi Kat,

I just got a jump in my Signatera from 2 to 22, and like you am stage 4 but should have had only microscopic disease left when the last measurement was taken. Even when I had all my tumors and nodes it wasn't anywhere close to that high

Like one of your repliers, I was also told dead cells could be the reason or an unrelated inflammation I had. The number made no sense - I'm told the tests are more accurate when they're negative.

So glad to see I wasn't alone. Thank you for posting. I hope your numbers have gone down on subsequent tests?

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Please everyone! Do not look at the specific signatura results (mtm/mL) or mean tumor molecules per mL of sample. They are meaningless and the only thing you should be looking for is whether you are negative or positive at any point in your trend or what the trend is. Please discuss this with your oncologist and remember Natera offers are free half hour consultation with every patient who's getting these results. I am a retired professional who spent many years in developing and validating bioanalytical assays of this type so I have some basis for an opinion. That being said I just returned from Mayo Clinic with some very surprising results. So one year after I had surgery for colon cancer, was stage 3 with two of 31 lymph nodes involved, I had negative CT DNA tests at post-op, and then three additional negative tests through June of this year. Today when I went in for my one year CT scan and colonoscopy and blood work, we found what may be metastasis to the liver, 2.0 x 1.6 cm. Very surprising and counter intuitive to the four consecutive and serial negative Signatera results. So after confirmation I may very well be stage four with metastasis to the liver. Just goes to show you that spending too much time on signatera is counterproductive. In my case the 10% false negative rate for this test may have given me false assurance.

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@roywalton

Please everyone! Do not look at the specific signatura results (mtm/mL) or mean tumor molecules per mL of sample. They are meaningless and the only thing you should be looking for is whether you are negative or positive at any point in your trend or what the trend is. Please discuss this with your oncologist and remember Natera offers are free half hour consultation with every patient who's getting these results. I am a retired professional who spent many years in developing and validating bioanalytical assays of this type so I have some basis for an opinion. That being said I just returned from Mayo Clinic with some very surprising results. So one year after I had surgery for colon cancer, was stage 3 with two of 31 lymph nodes involved, I had negative CT DNA tests at post-op, and then three additional negative tests through June of this year. Today when I went in for my one year CT scan and colonoscopy and blood work, we found what may be metastasis to the liver, 2.0 x 1.6 cm. Very surprising and counter intuitive to the four consecutive and serial negative Signatera results. So after confirmation I may very well be stage four with metastasis to the liver. Just goes to show you that spending too much time on signatera is counterproductive. In my case the 10% false negative rate for this test may have given me false assurance.

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Sorry to hear about your possible liver metastasis, Roy (and thank you for the really helpful perspectives on Natera testing and results). Just sharing that I had a very similar sized mass found on my liver in April. Showed up on routine CT as "very suspicious for metastasis" and then my liver surgeon confirmed at as 99% sure of metastasis based on how it showed up on the MRI. Had my liver resection surgery in July and when they got in there, they couldn't find anything. The surgeon spent an hour going over every part of my liver and even called in a radiologist to consult during the surgery. It was a rough surgery because they had cut adhesions to my intestines and other connective tissues to fully examine the liver, but they didn't find anything. My liver surgeon has been doing this for 25 years and is chief of surgery at Penn; he had no explanation and hadn't seen anything like this before. All of which to say, I hope your mass turns out to be negative as well. Wishing you all the best.

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@roywalton

I doubt that the numbers you refer to are Signatera, as these results are simply reported as either negative or positive.

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This is not correct info. I get the Signatera done as part of my bloodwork. It gives you actual numbers and a scale that shows an increase or decrease.

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@mindy514

This is not correct info. I get the Signatera done as part of my bloodwork. It gives you actual numbers and a scale that shows an increase or decrease.

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As @roywalton mentioned, tests results will either be positive or negative for the presence of tumor DNA in the blood.

If you have early-stage cancer:
A positive result means there is higher risk for your cancer returning. A negative result means that you are more likely to remain cancer-free.

If you have metastatic cancer:
Your doctor may look for changes in ctDNA levels to assess your tumor’s response to treatment.

Read more here: https://ce.mayo.edu/sites/default/files/Signatera%20Patient%20Education.pdf

@mindy514, you're right that results can change over time. It sounds like your team is using
Signatera testing to monitor your cancer. The overall result as well as the trend in the amount of tumor DNA detected over time can be used by your healthcare provider to make an informed a treatment plan personalized for you.

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@mrgvw

I love Roy's response... spot on. I'm certainly no oncologist or doctor of any kind, but I've been counseling hundreds of EC patients around the world for over 3 years. I'm only 4 1/2 years since dx, and just over 4 years post-op. I've had Signatera testing done every 3 months since Oct 2020.

I admit I'm puzzled when I see others reporting Signatera results while they are stage 4 and undergoing treatments. There's zero doubt your cancer is out and about and will certainly be seen in your bloodstream. But the relativeness of these numbers... I'm a bit suspect of. For many of us, Natera testing is started post-op, when it is believed we've reached NED status from all our chemoradiation treatments and subsequent esophagectomies. Are we truly NED at a month or two post-op... who the hell knows... and even our many doctors can not be sure. And if they tell you that you are now cancer free... They're full of sht... and irresponsible.

But... it's a good starting point, and if a zero baseline is achieved, future Signatera testing will be a good relative indicator of what's floating around in the bloodstream (ctDNA). But this is not the Be All End All... just another tool to monitor us like our scans and endoscopies and symptoms we are feeling. But again... I'm not sure just significance there is from running Signatera tests on active stage 4s receiving chemo treatments.

We do see protein monitoring in general... for CA 19-9, CEA, CA 125, etc. But even these numbers jumping around... can be a bit misleading. But Signatera testing... looking for YOUR cancer's signature in YOUR bloodstream, is different. All the best.

Gary

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@mrgvw Thank you for your comments. I was dx stage 4 appendix cancer in 2021. I started fortnightly CEA protein blood tests before my fortnightly Folfiri + Avastin infusions. I chose to leave Folfox to plan B if needed.

I asked my oncologist not to tell me my results, unless we needed to worry and look at Folfox. I didn’t want the stress if I didn’t need it. Only once was he concerned and said we may need to change after my next results. Next infusion he said any concerns had gone and it was business as usual. I have no idea what my numbers ever were. My choice.

After a year of various treatments including 2 major surgeries I was finally NED in 2022 . I chose to stop treatment then. I haven’t been treated since. My oncologist says my gamble worked for me and now we only attack if/when the cancer comes back on my tests. I am periodically scanned (3 monthly now 4 monthly) PET-CT and CEA etc blood tests and meet my oncologist to hear his take on the results.

I have never had Signatera but have read about it. Our Medicare system in Australia doesn’t cover it. In a way I’m glad I haven’t. This stress seems awful.

I hope everyone who is worrying about their Signatera numbers fights on if needed 🙏🙏 That’s my plan if my tests show anything that concerns my oncologist 🙏🙏

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