OUTLINE: This is a multicenter, randomized study. Patients are stratified according to Zubrod performance status (0 vs 1 or 2), discontinuation of oxaliplatin during first-line therapy (yes vs no), planned concurrent chemotherapy (FOLFIRI vs single-agent irinotecan hydrochloride), and time from last dose of bevacizumab (14-42 days vs >= 43 days).