Is CA 19-9 a lagging indicator? How is it used?

I am told that surgery with inflammation and sometimes infection (not related to cancer) can cause markers to rise.

I have had Pancreases cancer for 6 years and have had my marker all over the place. After eating a shake shake hot dog it raised it from 11 to 30 It has to do with a multitude of factors not just cancer. By the way I do not recommend hot dogs of any kind. I was treated with the Triplett At Virginia Piper Cancer Center in Scottsdale Az.
My last CA-19-9 was 14.7 I get results from blood in less than 2 hours

Thank you for the hot dog warning. I’ve been hearing a few warnings lately so have chosen to stay away. It’s sad because they had been a staple in my life since childhood!

My CA19-9 numbers have gone up and down the whole time but lately bounce around under 35. Onchologist says not to worry about it.

CA19-9 is not specific to PDAC pancreatic cancer. It will reflect other GI pathologies and is documented as a marker of various inflammatory processes, whether inflammation as a result of a post-surgical procedure, respiratory tract infection, immunological response to a vaccination, etc. it is a single point in time which on its own is not of diagnostic value. A trend occurring over a period of time would then warrant further investigation to determine origination of cause.

Thank you!
I will put the skyrocketing numbers down to postsurgical inflammation as you suggest just to save my sanity and wait for the next marker test to see the trend.

Thank you! I was not told this by the oncologist.

Triplet-gem/abraxane/Cisplatin?

When I was diagnosed in July 2023 my CA19-9 was 9700. I did 3 months of GA chemo before my surgery in January 2024. At that time my CA19-9 was 150. My pathology report was clear. Two months after the surgery it was 1820. I did 3 more months of GA chemo and it was 35. I have did Pet CT scans every 3 months since the surgery and they have always been clear. My oncologist stopped my chemo and told me to do scans every three months, and check my CA19-9 monthly. That was in October 2024. My CA19-9 has went from 35 to 371 in 3 months. My oncologist wants me to start chemo again even though my scan in November was clear. I am really confused about the numbers. I don’t really want to go back on chemo.

Please double check this with your oncologist but my understanding in layman’s terms is that cancer cells hide and are not always visible in scans. The elevated markers indicate their existence. So the recommendation to resume chemo is to prevent them from rising further.
All the best to you.