How do you choose a dose of 5-FU during chemo-radiation for a patient with rectal cancer who is dialysis dependent?  

5FU is not cleared by the renal excretion and does not require dose modification.  I would tend to use the doses in the NSABP R-03 trial, 225 mg/m2/day continuously.  Other published doses or bogus schedules may be equally used without dose modification. However capecitabine is cleared re...