OUTLINE: This is a multicenter study. Patients receive irinotecan IV over 90 minutes, leucovorin calcium IV, and fluorouracil IV once weekly for 4 weeks. Patients also receive bevacizumab IV over 30-90 minutes once every 2 weeks. Treatment repeats every 6 weeks in the absence of disease progression or unacceptable toxicity. Patients are followed every 3 months for 2 years, every 6 months for 3 years, and then annually thereafter.