Being a mathy kind of engineering geek, I can't resist commenting on this.
Maybe GrouseMan or DK37 can comment on this, but I assume that the intent of the pump is to keep the concentration of 5FU in your blood at a constant level for the entire 46 hours. It pumps enough 5 FU every 2 minutes to make up for the exponential biological decay that is a result of your body trying to remove this poison. If you start at 100% of the intended concentration using the bolus and the pump keeps the concentration level up, then you get the full effect for the entire 46 hours. But if you start at 0% (no bolus), it takes about 8 hours to get up to the full concentration.
So, have there been studies on having the pump + bolus for 38 hours? Or pump (higher delivery rate) without bolus for 46 hours? Either way, even if you get the same mass of the drug, you do not get the same concentration for the intended period of time. Does it make a difference? I have no idea, and I wonder if your onc does.
DW, Sleen dx 9/2013 @47yo: IIIc T4b N2b MX
10/2013 - 3/2014 FOLFOX
4/2014 - 6/2014 Rad to bladder
12/2014 +'ve for lung mets, MX becomes M1
3/2015 enter TIL trial @ NIH
7/1/15 Receive 148E9 cells to target K-ras G12D mutation
8/11/15 Reduction=18%, no new tumors
10/20/15 27%; PET -> one hot met
11/24/15 30% all mets shrinking
1/26/16 46% but one suspicious met
3/24/16 46% but one growing
4/7/16 Lung lobectomy NED for the first time
3/3/20 Still NED "cured"