Speedy update: I just got my CA 19-9 back from Tuesday, which was taken after chemo cycle 13 but before cycle 14 was administered. It's now down to 29, which is 6 points lower than the test taken 11/14. It also represents, now, five cycles without oxaliplatin. So again, I'm just one person reporting continued results without oxali. Others have seen a rise after discontinuing oxali. Correlation and causation are two different things, both in my case and others' cases. Correlation is not the same thing as causation. If the OP's and others' results continue to rise, it's worth pursuing the causation, as I will if/when mine rises.