Bevacizumab Plus Fluorouracil and Leucovorin in Treating Patients With Locally Advanced or Metastatic Stage IV Colorectal Cancer That Has Progressed After Standard Chemotherapy

RATIONALE: Bevacizumab may stop the growth of tumor cells by blocking the enzymes necessary for cancer cell growth. Drugs used in chemotherapy such as fluorouracil and leucovorin use different ways to stop tumor cells from dividing so they stop growing or die. Combining bevacizumab with fluorouracil and leucovorin may kill more tumor cells. PURPOSE: Phase II trial to study the effectiveness of combining bevacizumab with fluorouracil and leucovorin in treating patients who have locally advanced or metastatic stage IV colorectal cancer that has progressed after standard chemotherapy.