Irinotecan With or Without Oxaliplatin in Treating Patients With Metastatic Colorectal Cancer

RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. It is not yet known if irinotecan is more effective with or without oxaliplatin in treating metastatic colorectal cancer. PURPOSE: Randomized phase III trial to compare the effectiveness of irinotecan with or without oxaliplatin in treating patients who have metastatic colorectal cancer.