Do you routinely utilize G-CSF as primary prophylaxis in patients receiving mFOLFIRINOX or FOLFOXIRI?

Interesting to see the differences. I can't speak for others in our large GI practice but as we see well over 1000 pancreas cancer patients/year, there is substantial experience with FFX. I personally do not use primary prophylaxis and I/we do not routinely check DPYD. If neutropenia occurs, we add in pegfilgrastim at the time of pump disconnect. So far, that seems to be going fine.

Yes. Routinely. Based on the Yale study of modified FOLFIRINOX (Stein, et al, Br J Ca: 114, 806, 2016), minor reductions in bolus and FU with peg-filgrastim reduced rate of grade 3-4 heme toxicity to 12% with only 4/74 patients having neutropenic fevers. Efficacy appeared equivalent to PRODIGE study.

At my center, we treat about 40 patients/year with modified FOLFIRINOX (no 5-FU bolus, irinotecan at 150mg/m2), and we do not use cycle 1 pegfilgrastim. Febrile neutropenia is very rare, and the addition of pegfilgrastim is also rarely required. We do use routine DPYD genotyping prior to 5-FU chemotherapy, and the patients with DPYD variants get a dose reduction of the 5-FU infusion (per CPIC guidelines). I do think that this pre-emptive screening for DPD deficiency contributes to the safety of not using prophylactic pegfilgrastim with mFOLFIRINOX.

I agree with others that as long as the interval to the next chemotherapy treatment is around 12 days, pegfilgrastim is safe (doesn't need to be 14 days or more).

Agree, regularly use at disconnect prophylactically. Given short half life of the 5FU, feel okay giving on same day of disconnect.