I posted the below verbiage on another support forum. Felt it was just easier to copy and paste here.
Quick summary of what has transpired this year with my CEA levels. March 20th, CEA spiked from 5.2 in December to 15.6 during a routine 3 month checkup. Retest done March 22, CEA is 16.7. A series of diagnostics were done: colonoscopy, CT w/contrast, PET/CT, small bowel capsule endoscopy, endoscopy with targeted ultrasound, and MRI with contrast. While there were some issues found there was nothing cancer related.
Meanwhile more CEA tests were done. May 2nd, CEA 14.2. June 19th, CEA 11.9. So things were trending back down and it appears whatever is causing it seems to be resolving itself. September 18th, during another 3 month checkup, CEA 15.2. Ok, why the unexpected spike? My oncologist feels there's nothing to worry about. I sat on this till early this month when I decide to talk to my GI doctor to see what he thinks. He feels there's something going on but to run blood work to see where I am now. November 8th, CEA 20.2. Ok. What the heck is going on? Talk to my oncologist. He says he still feels there's nothing to be concerned about but to set up an appointment with him so we can discuss further in person.
Appointment was set up on November 14th. We talked about why he think there's nothing going on with me which indicates a recurrence or metastatic spread. He said something which provides some clarity on CEA in general. He said CEA is not a primary diagnostic tool and is never used until someone has had a confirmed case of solid tumor cancer. Afterwards, CEA is used to see if something may be happening to initiate further diagnostics. He said typically tumors in the colon will not spike CEA. It's when there is metastatic spread is when CEA jumps...typically. He said I've always been on the high side with CEA. Even with the CEA spike I had last year where it went from 5.6 to 9.7 to 11 and then back down to 9.7 prior to the right hemicolectomy to remove a cancerous polyp in my appendix, he felt the CEA climb wasn't due to the polyp but just coincidence. He said it's a shame a long term baseline of my CEA levels wasn't done prior to being diagnosed with cancer. He thinks this fluctuation is just my normal as it's been years that I've had elevated CEA with clear scans and no symptoms.
But he went ahead and ordered another round of blood work along with a CT w/contrast. So my CEA on November 14th was 14.3. An almost 6 point drop in less than a week. I got the results back from the CT scan last Thursday which said I am still NED. All the blood work I've referenced above were done at Labcorp so there was no interlab variability.
So it appears my doctor has been right all along. I wanted to put this thread out there as there appears to be no one posting on the Internet that has followed up on their high CEA levels to the extent I have. I know when I was hunting for answers it was frustrating to read about someone that started to exhibit the same CEA behaviors as me but then drop off the face of the Earth. I'll continue to update my situation to provide a long term record of my progress. The recent results prompted my oncologist to stay with my graduation to 6 month checkups now.
As a parting gift, I found a medical paper about a patient in Taiwan who was treated for colon cancer to later have a recurrence in her ovary. Her CEA history ranged from a spike of 1500 just after the surgery to remove her ovary to a low of 68.5. The doctors administered oral 5FU which didn't have an affect on CEA. She was followed for 5 to 6 years with periodic scans done along the way. They never found any additional metastasis during this time. Here is a link to a summary of the paper. Unfortunately, I can't directly link to the actual PDF.
https://academic.oup.com/jjco/article/36/12/811/874390
Oh and it looks like I'll be crossing that golden 5 year mark being NED since I was diagnosed back in Dec. 18, 2012 with my initial cancer diagnosis; stage 3b colon cancer.