OUTLINE: Patients receive arsenic trioxide IV over 2-4 hours for a maximum of 25 cumulative days followed by a rest period of 3-4 weeks. Patients with complete or partial response may receive 6 additional courses in the absence of disease progression or unacceptable toxicity. Patients with minor response (25-50% tumor regression) may also receive further courses of treatment. Patients are followed at 4 weeks.