Personally, I am a fan of the CA 19-9 marker, I had a Whipple procedure in 2018. Cancer returned in 2023 and the CA 19-9 marker increased steadily tracking the Pancreatic Cancer. After successful stereotactic radiation treatment the marker decreased to below 34. Last year in 2024 my markers started increasing again and again a pet scan showed that it had returned. I am currently undergoing chemotherapy and after one month, the CA 19-9 marker decreased from 1500 to under 500. For me, the marker has been 100% reliable on tracking the state of my pancreatic cancer. I do agree with the comments here that say you have to get a trend line and one test may not mean anything unless it’s really high. God bless you and I pray for your recovery. 🙏🏼