I'll be 71 next month, stage 4, inoperable adenocarcinoma in the body and some abdominal lesions, but no lymph node involvement. I currently receive modified Folfirinox chemo. I assume your dad's oncologist doesn't want to provide the full, 100% dose to your dad because of age. Mine didn't either. As he pointed out, the dosage level was tested on people much younger than me; it also tends to result in a 10% hospitalization rate overall. So he reduced the dosage. Cycle 1 was at 80% of full dose, and it was arduous--lots of nausea and diarrhea that were difficult to control with meds. Beginning with cycle 2, the dose was reduced to 60% of full dose, and I've tolerated that much better. So far, it appears to be effective: My CA 19-9 has fallen dramatically, and my oncologist is suggesting that, depending on future test results, I might be a candidate for maintenance therapy. I have never tried the regimens that were suggested to your dad, but as you ask questions about treatment, ask the oncologist whether the Folfirinox dose can be reduced and still provide effective treatment. It might give you another good option to consider. (I see that @markymarkfl mentioned that Folfirinox causes little hair loss. In my case, my hair was coming out by the handful, so I buzzed it off. It has never come back, and I've even had a 6-week chemo layoff recently. C'est la vie...)