CA19-9 Test: How often to test?

How long ago was the surgery, how long was your adjuvant chemo, how often will you be getting scans and ctDNA tests, and what have your CA19-9 levels been since surgery and since adjuvant chemo ended?

Were you declared "NED" based on surgical results + imaging + CA19-9 + Natera?

I'M NOT A MEDICAL PROFESSIONAL, but I guess it depends on how well you know what your typical CA19-9 values are, and how stable the doctors consider you to be. However, being only 1.5 years out from the end of your chemo, I would consider 4 months a bit too long for comfort as well. A LOT can happen in 4 months, and the slowly rising CA19-9 actually signaled the beginning of my post-Whipple recurrence before imaging or Signatera ctDNA tests did.

(I went from NED for 3 months after a "perfect" Whipple to recurrence spotted on MRI at the 4.5 month post-op mark, with EUS/biopsy and 2 Signateras being negative, before another Signatera barely registered positive 7 weeks later and MRI confirmed mets along with the primary tumor growing. So, basically 6 months from Whipple to Stage-4. CA19-9 in that interval went from 12 to 33 to 77 to 277, and then 678 in 6 more weeks before I resumed chemo.)

Now on biweekly chemo for the recurrence, I get CA19-9 tested every two weeks along with CBC/CMP and the others necessary for another round. My last (local) oncologist would only test every 4 weeks while I was on my bi-weekly pre-op chemo. I was a bit frustrated by that, and got my primary care doc to write me an order for repeat/serial testing that I could take to a walk-in lab myself and self-pay ($25). Cheap enough for the peace of mind... So I was getting tested every two weeks, but at different labs. Their scales were different so the results were not directly comparable, but by keeping them separate for analysis, I had a better picture of the upward trend from both labs telling me the pre-op Folfirinox wasn't really doing much.

If you're starting with a new oncologist and a new lab, I (personally) would try to get tested every month to understand your normal values and trend, and then see how your new doctor's results match up.

But to be honest, if you've already had PDAC, I would be looking for another specialist closer to home. This one doesn't sound very aggressive, and I would worry as much about his/her response time as much as detection time.

Thank you for your thoughts about this and letting me know your testing schedule. I think a monthly test is still warranted, at least through my next scan in March -- in case the date needs to be moved up.

First, I am continuing with the cancer center that did the surgery and chemo on the mainland for scans and ctDNA tests for recurrence monitoring and expertise. The problem is, they can't order blood tests or any medication (should I need it) in my state (Hawaii), so I also need a local oncologist. There are no Pancreatic specialists locally available. There are many good oncologists for other cancers, but PDAC is rare here as far as cancers are concerned.

Second, I am 18 months from my last chemo and have been NED on all my scans except for a small spot on my liver they have been watching. My CA19-9 has ranged from 7-8, with a high of 20 prior to surgery (stage 1, nodes were clear). My first three ctDNA results were negative. I still have my port as they preferred I keep it in. My next scan is in March 2024. That will be my 2-year scan from my last chemo. I'm 77 and that's part of why they are cautious.

Recurrence is a concern, as you know. To hear a staff member from the local doctor say that I should let them know if I have any symptoms is a "red flag". Sure would be nice if there was an "early warning" system for this cancer! I think four months is too long for someone so close to surgery/treatment (regardless of initial tumor stage), but have no idea how other patients are monitoring their situations and if there is some sort of standard the major cancer centers tend to follow in terms of monitoring. If the consensus is more frequent testing, then I may be able to get some help getting more frequent tests.

For what it's worth, my original oncologist seemed to write me off when I got my stage 4 diagnosis. I had a CA 19-9 and CT scan in March, then not again until June. Many things, including the sporadic testing, led me to "fire" that oncologist and switch to another one in the same practice. This MD tests CA 19-9 every two weeks, and I have CT scans every two months. (FWIW, this oncologist trained at Mayo and MD Anderson.) I am in chemotherapy right now, FYI.

I would be really concerned about being told to look out for warning signs and let them know if I have a problem. By then, you may be out of luck. I understand that you're in Hawaii. Is there anyone at the Burns Medical School who can take your case? Also, have you scanned all the various lists of cancer centers to see if there are any in Hawaii? Can your mainland medical provider work more closely with your Hawaii provider?

@patti303 , now that I see your geographic situation, I understand the rest. 🙂

If you don't have any other realistic choice for a local oncologist, I would be as nice as possible to this one. But maybe voice your concern about how fast you've seen CA19-9 change in others with disastrous results, and (honestly) how you'd be more comfortable continuing the monthly testing trend of your previous specialist, at least until you've gotten a few tests under your belt.

Most oncologists agree that raw CA19-9 numbers and blind testing of people with no history or risk factors is not good as a diagnostic tool, but now that you've had PDAC and know your CA19-9 history and recent normal numbers, I think many would agree that a rising trend is reason enough to expedite other testing.

Aside from ctDNA, imaging, and symptoms, what else do you have to go on? CA19-9 is the easiest and cheapest, thus realistic to do most often. Offer to self-pay if you can find a reasonably priced lab. mdsave.com and "Any Lab Test Now" are two avenues that might find you a manageable price. If the local oncologist still doesn't agree to it, see if your local PCP will order it.

After your hard-earned success getting to NED at this point, recurrence with metastasis is the last thing you need!

Aloha -- mm

Question- we were told CA19 test was pricey so that’s why they only do it once a month.
Also told, that this number is not the be all end all, although it’s a good checkpoint.

I can't speak to the pricey part due to the way my insurance works. @markymarkfl has always said that he independently found a lab that would do the draw and process the test for a very reasonable out-of-pocket fee (I think $25). Whatever you wind up doing, be sure to have the test processed at the same lab each time. The results apparently can vary if the processing facility changes. Re the reliability of the test, you're right--the CA 19-9 isn't the ultimate authority. In particular, it's a lousy diagnostic tool. However, it can be a good tool to track treatment progress and disease status.

@cpmcb , I went to mdsave.com, entered a zip code for Orlando (Central) Florida along with the CPT code (86301) for CA19-9, and got the following result:
https://www.mdsave.com/f/procedure/immunoassay-tumor-ca-19-9/AQABAKUAtlUNAzuIOUSDCBeUKOxbYp2Nha6rEn9C13u7Q92p2FR6JT0Zs9jOy_G4yv8hQawhU8IRMkCj5cZ8OXuZVwhPnc32FG0ApMWFf4ypG91uymbpRQJuxvjXMi8bWZmt2Nx24xaCxC35y8oFABlw5kBuy2n7aP8wkISAIErpVMkKIYXv78ub3UPsoboDYuyv8W1xv_5AdxjBEDy8a_pDchXKTFSyu4pu1rD3UGOOHmV-u8FBRmR0olrLazHSouQCT3shdwZ70Cs?q=86301&name=Immunoassay%20Tumor%20CA%2019-9&latLng=28.5988789,-81.2036885&city=Orlando&state=Florida&zip=32816
It says the Estimated National Average is $92, the MDsave regional average is $45. It returned 9 individual labs from 5 multi-site health care companies, with a price range of $32 to $64. I used one of them a couple times directly (independent of MDsave) and got a cheaper price (the $25 to $30 range).

https://www.sonoraquest.com/patient/knowledge-center/discounted-pay-at-time-of-service-rates/ was $56 (for Test Code 3698)

https://requestatest.com/cancer-antigen-ca-19-9-test $69

https://www.walkinlab.com/products/view/carbohydrate-antigen-ca-19-9-blood-test $53

https://onetestforcancer.com/buy/?step=main-product ($189 for 6 biomarkers or $269 for 12 biomarkers)

This site returns a range from $37 to $161, and indicates some states where the testing is blacklisted. https://www.findlabtest.com/lab-test/cancer-screening/ca-19-9-test-quest-4698

Some of them might take a little digging if they're only listed by CPT code or ICD-10 code or the specific lab's test number, but I think you should be able to price-shop in your area and find something affordable.