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 renally and sho...