@wjk , I was tracking my CA19-9 at 3 different labs (for weird reasons), but was in the neighborhood of 200 one month before Whipple, and 12 one month after Whipple.

The pre-Whipple trend was inching slowly upward, which means the Folfirinox might have been keeping things from "getting worse faster" but not really doing anything to lower it. The surgeon basically wanted to see some level of pre-operative control before operating. Not sure why, but since my recurrence and CA19-9 near 700 at the beginning of treatment, I've responded way better to Gem+Abrax+Cisplatin than I did to Folfirinox -- found it easier on my system too.

[As an aside, that's one of my frustrations about some of the "stay the course and observe" styles of treatment -- they can waste time before determining that a different treatment might be more effective.]

In your case, I don't know if a jump from 43 to 153 is too significant or what the cause might be if it's real, or if that would impact the surgeon's plan. I certainly hope not! One big question would be whether the CA19-9 is being shed from cells in the original tumor or from cells that started floating around elsewhere.

One thing the surgeons typically do when they open you up is start with an exploratory laparoscopy -- just looking around with a camera for signs of spread that may not have been detected on imaging. That's often the point where they might abort, rather than just depending on CA19-9 and/or imaging. (My last MRI was one week before Whipple, so the info was very current, but the surgeon still performed the laparoscopic inspection before my full open Whipple.)

Since you're off treatment for around 6 weeks before surgery, and probably will be off for 6 weeks after, there is a definite risk, as we know with this beast. I don't hear about many surgeons being willing to step outside of the box, but if I could direct my own treatment, I would ask about a few add-ons:

1) Could a systemic treatment like immunotherapy, PARP inhibitor, etc... be used in the interim without messing up blood counts before surgery or impeding healing after surgery?

2) Could a "physically regional" therapy like Tumor Treatment Fields be used in the interim attempt to help control the spread (without any side effects)?

3) Could they do an open Whipple instead of laparascopic, and add the HIPEC therapy during the operation? If there's any microscopic spread they don't see in the peritoneal area or at the surgical margin, doing the heated chemo wash might help kill those cells. It would basically be "one free chemo treatment" (not systemic, but more regional than surgery) in the middle of your otherwise 3-month hiatus from treatment.

4) If they see any problem with surgical resection of the pancreas, could they switch modes to something like IRE (Irreversible Electroporation) while they're in there.

Those seem like feasible (to me, non-medically trained!) backup plans to get the most bang for the buck while you're under anesthesia and having insurance pay for what might be your one big shot.