OUTLINE: This is a randomized, multicenter study. Patients are stratified according to center, percentage of liver involvement on CT scan or MRI (less than 30% vs 30% to under 70%), prior chemotherapy (none vs adjuvant chemotherapy comprising fluorouracil (5-FU) and leucovorin calcium (CF) or 5-FU, CF, and levamisole (LEV) completed at least 1 year before study vs adjuvant chemotherapy comprising 5-FU with or without LEV completed at least 6 months before study), and synchronous disease (yes vs no). Patients are randomized to 1 of 2 treatment arms.