@priscwy this is a great question especially to me as it was basically the first question I had when I got onto this group in late 2023. However, to be answered properly it needs a bit more background info such as are you currently receiving chemo?, what are your mutations (to determine aggressiveness), what type of PanCan do you have? Following surgery and then 12 sessions of chemo and then no chemo for 4 months my ca19-9 started to rise from pretty much stable 1 digit (6,8) to 23. I did become worried especially as during chemo treatment it was noted I had an area of concern around the celiac artery (a common path of progression) though it was brushed off by radiologists as scar tissue; though I was never fully convinced by their interpretation. Also possible it could be inflammation. The best thing is to repeat the test in 2-3 weeks and see if that number is rising; particularly if it is multiplying rapidly. I number seemed to increase each time by a factor of 4. Before I could convince my dr and their staff that it was my cancer “reappearing”, 2 months had gone by and my ca19-9 at 3840. It did respond to chemo. I got my kind primary dr to order CA19-9 test more often (every 2 weeks), when my oncologist team wouldn’t listen to me. Good to be aware and concerned even if it goes back down. At least you are being your own advocate and that’s the best position to be in, I think.