Combination Chemotherapy in Treating Patients With Advanced Colorectal Cancer

RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining more than one drug may kill more tumor cells. Leucovorin may increase the effectiveness of fluorouracil by making tumor cells more sensitive to the drug. PURPOSE: Phase II trial to study the effectiveness of combination chemotherapy consisting of oxaliplatin, fluorouracil, and leucovorin in treating patients who have colorectal cancer.