Combination Chemotherapy in Treating Patients With Recurrent Metastatic 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 and giving the drugs in different combinations may kill more tumor cells. It is not yet known whether receiving irinotecan with fluorouracil and leucovorin is more effective than receiving oxaliplatin with fluorouracil and leucovorin in treating recurrent metastatic colorectal cancer PURPOSE: Randomized phase III trial to compare the effectiveness of irinotecan with oxaliplatin followed by fluorouracil and leucovorin in treating patients with recurrent metastatic colorectal cancer.