Signatera Numbers are sky high and I'm terrified

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