CA 19-9 and pancreatic cancer: What do the numbers mean?

Having an adenocarcinoma and not being a secretor of CA19-9 is known and documented. Approximately 10% of the Caucasian population of North America are non secretors. The cause is related to the Lewis antigen which determines blood group factor. Those with the genetics of the gene that codes for the antigen having Le-a-, Le-b- are non-secretors. Their CA19-9 value will range between -3U/mL and +3U/mL. The reason it is possible to have a negative value is that the inherent error of measurement is +/-3.

My husband was also a stage 1B. Had Whipple in Feb and currently received treatment #9. His CEA numbers were in normal range and CA-19 fluctuates. Was wondering how you are doing and if your Oncologist had any thoughts to reliability of these numbers during Chemo. Thank you.

Hi,
I am still ( since April 2023) on Gemzar/Abraxane (second reduced dose), after Folferinox failed in its six months trying to chase down cancer cells floating around in my bloodstream. Now, they set up camp on my liver. My oncologist looks at trends with CA numbers. I trended up when I started Gemzar, but next test went down. Doctor thought the trend up was attributable to new regimen after a break in treatment. Lots of variables, it seems, affect CA results. Best wishes, and I hope this helps a little.

My body doesn’t make CEA or CA 19-9; totally non-existent even with biopsied cancer present. Mayo said your body doesn’t make them - can’t be used. We watch CT scans. It’s frustrating because others can do blood work once a month and get an idea. I’ll ask if there is any other way on my next visit.

@lvtexas , Did they get enough malignant tissue from the biopsy to "build" a Signatera test?

This is a test that extracts DNA tissue from your original tumor, builds a special "filter" to exactly match its DNA, and then checks later blood samples for evidence of ctDNA (Circulating Tumor DNA) with exactly that pattern. It provides a numerical result in tumor molecules per milliliter, and the trend over time can indicate the response you're having to the chemo.

Ideally it detects the presence of cancer before standard imaging does, but it's not a perfect test (twice returned zero-point-zero while my recurrent tumor was growing) and didn't return a positive (0.14) until after imaging did and my CA19-9 was near 300 (after that post-Whipple low of 12). Since my chemo resumed, the CA19-9 levels have dropped, and the Signatera numbers have all gone back down to 0.00 (which they note doesn't mean no cancer, just below their ability to detect). My PA said if it's > 0.00, you do have cancer, but if it's negative (0.00) it doesn't mean you don't.

We had lots of tissue from my Whipple procedure, and we re-run this Signatera test every 2-3 months to get data that supplements my biweekly CA19-9 tests. I hope they can do this or something like it for you.

I occasionally get static from my insurance company about the Signatera test "not being medically necessary," but always find a way to get it covered. Since you don't produce CA19-9, I think it would be easy to justify as medically necessary along with scans.

I agree. Signatera test is another data point, of which we have very few, without scans every 3months

Mine was at 0 after I was declared NED but rose to .04 in June, in tandem with my CA19-9 rising. Sure enough, a 1 cm tumor reared in my liver. So VERY GLAD all of these screening tools are there. I have the KRAS G12D mutation and am lucky that CA19-9 seems to trend with my disease. There is no immunotherapy or treatment options matched with this mutation as yet. BUT-both fulfurinox and now Gemzar are working! 22 months and thriving!!

My husband was diagnosed with PanCan in April 2022. He underwent a chemo regimen but turned out to be allergic to the chemo drug. It caused major problems, including blowing out his prostate, which backed up into his bladder and kidneys and did major kidney damage, leaving him with end stage renal disease (currently on home dialysis). He was not considered eligible for surgery because the tumor was right next to major arteries. He had a series of radiation treatments, and eventually when he was almost maxed out on radiation they decided to do internal radiation. They radiated the tumor, after which the CA19-9 stayed mostly on the 30-40 range from July '23 to May '25 except for one blip to 93 in May '24. But in May '25 to went up to 170, in June 235, in Aug 393, and now 2,311. Yikes! The August CT showed no visible changes or metastases. Will be having another soon, but very curious about what else could be pushing it up. Any thoughts?

I have had a similar experience. I have had two needle biopsies. Both came back as essentially strange cells, but no diagnosis then I underwent chemotherapy and after that a combination of chemotherapy and radiation. My last visit indicated I was not a candidate for surgery for the same vascular reasons as your husband. There has been no sign of metastasis my C 19 got down as low as 300 and now is going way back up in spite of no radiological evidence for spread so they gave me one of three choices do nothing and follow up every six weeks, take a light pill Chemotherapy, or take a full on chemotherapy. I decided to do nothing because there is a chance that this could be due to a focal pancreatitis. I am not saying that it is I’m just saying there is a chance so my thoughts are with you because we’re sort of living in a gray area. It’s hard to think about the future and at the same time you feel like you’re in an airport waiting for a flight to take off that never seems to. I am personally, trying to figure how one deals with this situation. My current thinking is to just go on living and see how things play out. I am 75 years old and when you think about it, if I was deemed healthy for my age, anything can happen healthwise after you pass 65. In other words after that age, everyone is waiting for the other shoe to drop. I was a scientist and a college professor during my career and I think there is some value to just accepting the status quo. Unless something, in regards to care, that speaks to more effective treatment presents itself. I am sorry that I could not present you with a more definitive answer, but I honestly don’t think there is one to be had.

What makes this journey scary is that things are unpredictable, nothing is for certain, so there’s always the question- will my next scans be clear? Or will the worst happen and I’ll - without any warning - have a reoccurrence?
You sound younger than me (I’m 72-feel young though!), so harder to deal with for sure.
I hope you’re staying hopeful, I know it’s hard. But what else can we do?
Every night I go over in my head the things I enjoyed that day, and I do my best to stay thankful for every day and the good things in my life.
I’m going to my Y 3 days/week, exercising really helps me! Endorphins, etc. And my goal is to send the message to my body that I’m strong and not going anywhere any time soon.
Looking forward right now to 2 things that I plan to be around for - my first grandchild is due February 2026 🤗, and my first book (I took up writing later in life - about 10 years ago) is going to be published March 2027.

@markymarkfl Hello! I am doing Signatara now. I had a recurrence in March 2025. Back on Gemcitabine/Abraxane chemo now off of that. But Signatara is being followed now.