Hi Jj950,
CA 19-9 numbers are just one piece of information among several that doctors use to make treatment decisions. One of my doctors told me that he looked for a doubling or tripling of the number. Complicating this topic is that sometimes the treatments themselves can temporarily raise the number.
Doctors can’t base treatment solely on a tumor marker because the number does not say anything about where and how the cancer is evolving. Usually the next step if a rising tumor marker looks concerning to the oncologist, is to order scans to take a look at what is going on. When are your next scans planned?
Regards, Mary