I've read so much about the CA19-9 markers and still get confused about it. I heard that it could rise after starting chemo or being off it and then back on it.... Has it gone up more than one time?

My wife's ca19-9 dropped consistently throughout 9 folfironox treatments and further after sbrt prior to surgery. During surgery, the biopsies and margins were all negative. The surgeon said that the tumor was fully necrotic and no further chemo or radiation required. The first ca19-9 after surgery was under 30. In 3 ca19-9's in the 5 months since surgery it has risen a bit to almost 60. Her MRI's and CT scans have all been clear. The oncologist says that her liver numbers are still far out of whack from the chemo and that has an effect on the ca19-9 readings. Assuming the oncologist's assessment is accurate, liver function also impacts the ca19-9 reading.