Combination Chemotherapy With or Without Bevacizumab Compared With Bevacizumab Alone in Treating Patients With Advanced or Metastatic Colorectal Cancer That Has Been Previously Treated

Randomized phase III trial to compare the effectiveness of combination chemotherapy with or without bevacizumab in treating patients who have advanced or metastatic colorectal cancer that has been previously treated. Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Monoclonal antibodies such as bevacizumab can locate tumor cells and either kill them or deliver tumor-killing substances to them without harming normal cells. Combining monoclonal antibody therapy with combination chemotherapy may kill more tumor cells. It is not yet known if bevacizumab is more effective with or without combination chemotherapy in treating colorectal cancer