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Does a change in CA19-9 indicate change in tumor?
Pancreatic Cancer | Last Active: Nov 16 6:14pm | Replies (41)Comment receiving replies
CA19-9 is not specific to PDAC cancer. There are many things that can afrect its value both benign and malignant. CA19-9 is affected by inflammatory processes of which a patient might not even be aware of another underlying pathology at play such as a sub-clinical Covid infection. This is why an oncologist will never make a treatment decision based on a CA19-9 value. If an upward trend is observed, it would trigger an oncologist to perhaps do a scan at 2 months rather than wait three months.
It is the comparison of index tumor(s) in a prior scan to a current scan that is used in basing the treatment decision. It is practical to use CA19-9 in association with tumor size. Far too many variables can effect it from genetics to certain products containing Biotin (Vitamin B-7 and even a report of excessive tea consumption causing a rise in CA19-9 but no tumor or a tumor shrinking.. This phenomenon is well documented and published. Don’t get obsessed with the CA19.9 value.
RISES IN CA19-9 at start of chemo
https://www.sciencedirect.com/science/article/pii/S2468294221000952
Replies to "CA19-9 is not specific to PDAC cancer. There are many things that can afrect its value..."
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If a couple doctors had gotten obsessed with my CA19-9 values, I might be cancer-free now instead of stage-IV with a feeding tube.
You are correct that it must be accompanied by other supporting data. Elevations or rising trends should be investigated promptly and seriously.
Although there are many benign causes, PDAC (initial diagnosis, progression, metastasis) is among the worst possible causes, and thus deserves to be ruled out first.
My multi-year set of biweekly CA19-9 data has been a pretty reliable indicator/predictor of chemo dose changes/effectiveness and disease progression -- cheaper and earlier than ctDNA and imaging (which later confirmed what CA19-9 had been "suggesting" all along).