ARM I (Feasibility assessment of VTCB): Patients receive bevacizumab intravenously (IV) over 30-90 minutes on day 1, vincristine sulfate IV on days 1, 8, and 15, and topotecan hydrochloride IV over 30 minutes and cyclophosphamide IV over 60 minutes on days 1-5. Treatment repeats every 21 days (except during weeks 14, 15 [course 5], 17, 18 [course 6], 26, 27 [course 9], 29, and 30 [course 10] when no chemotherapy is given) for up to 12 courses in the absence of disease progression or unacceptable toxicity.