CA19-9 rise while on maintenance chemo

I am not a medical professional of any type, only a patient. So I can speak only from my perspective. In my case, I was on modified Folfirinox, then modified Folfiri for a total of 26 rounds. (We dropped oxaliplatin after eight in order to minimize neuropathy.) My CA 19-9 went below 35 and stayed there for 4-5 months. Last spring, it began rising and made it up to the low 100s. My oncologist told me that this likely meant chemo resistance--that is, the cancer had become used to the drugs and was revving up activity despite the regular chemo treatments. To make a long story short (we've had a couple of bumps in the road), we did chemo radiation for 15 rounds over the summer, but no Folfiri. My oncologist said yesterday that we need to get back on systemic treatment in order to reduce cancer activity. My CA 19-9 ws 217 at last check. We're going to do one round of modified Folfox (no irinotecan, but yes oxaliplatin) next week as a place holder while he obtains permission to switch me to GemCis (gemcitabine and cisplatin). I certainly can't advise you to pursue any treatment or demand new scane or anything, but I agree with your idea to contact your husband's oncologist and inquire about the rising CA result. That may open the discussion you seek regarding why the CA is rising and what you can do to beat it back down again. Good luck and best wishes!

@sheridandb,
I have a somewhat similar situation, however I’ve been on GAC chemo maintenance since January and my last CA19-9 went from 197 to 536 the other day all in a matter of 1 week. I started out at about 3840 in January and the lowest I got to was 17, and then had a 2-3 chemo vacation in July. Had a CT early July that showed a decrease in my liver lesion. Not to scare you, but things can change very fast with pancreatic cancer. I sent a message through the portal to my medical oncologist and got a MRI yesterday and will be getting a PET scan today to see where growth is occurring. I was on 5FU last year for 12 cycles following my distal surgery in Oct, 2022. I think it’s amazing that you can handle 5 FU as maintenance as it’s the stringer of the chemos. My husband is wanting to ask my oncologist if I can go back on it again but I’m looking for ablation procedure of liver lesion if that’s where the growth is. Your disease appears to be similar to mine and I think you should ask for your scans to be done now. Best wishes to you!

Agree, contact your oncologist now, good luck!

Thank you. I've sent a message on our oncologist's portal. We/he knew that at some point there would be resistance to the current drugs, but I was hoping it would go on longer as Dan has finally begun being able to function more normally. The first 12 horrible treatments left him weak and unable to eat and pretty much tied to the couch. But the 4 months since then have gradually given him some life (and appetite) back.
Dan does have a scan scheduled for late September, but with these number increases I'm wondering if that should be moved up. Anyway, it is in the oncologist's hands now.
Thank you for your quick replies ncteacher, marienewland, and dalegantous!

Yes, I moved up my scans and got them completed yesterday. The sooner you know what and where growth is happening, the sooner you can try and do something about it. Just tell people scheduling scans that you have an increase in your tumor market as that is one of the billing service codes and you should be able to get one very quickly.

Yes. I ditto what all have said. Resistance to drugs happens differently for all of us but rising CA19-9, if a trend, is always a reason to scan.
Be sure to ask your doctor about clinical trial drugs as well.
We’re you on the folfuri maintenance called Xeloda?

According to reports, the maintenance is 5FU/leucovorin.

We've talked to, or left messages with oncology, radiation oncology, and our navigator so I'm sure the oncologist will get some messages when he returns next Monday.

Thank you for your response.

Thank you for your remark about the billing service code! We had next week "off" from medical appointments, so our schedule is very open if they have the time for us.

Just re-read my original post... and Dan's CA19-9 was over 39000 (not 3900 as I wrote). Now between 500 and 600... but a month ago it was between 300 and 400.
His oncologist is continuing with the maintenance regimen next week, saying that the numbers can fluctuate. There have been two in a row that went up instead of down. The next CT scan is in a month. Last one showed an increase in size of one lymph node, behind the abdomen. Otherwise scans have been pretty stable.
Have to admit that Dan has felt so much better on the maintenance chemo compared to "the whole kitchen sink" chemo that it has been good to see him able to get off the couch.
But we will watch the numbers... blood test is being done every other week when he gets chemo. Thanks everyone for your thoughts/advice.