5. Patients will be stratified by liver function tests: Normal liver function: Total Bilirubin </= 3 mg/dL, Alanine aminotransferase (ALT) </= 5 times upper normal reference value. Abnormal liver function: Total bilirubin >3 mg/dL and/or elevated ALT > 5 x upper limit of normal (ULN). If bilirubin is >/= 5 mg/dL, fluorouracil (5FU) dose will be omitted. Both of the above groups will be eligible.