OUTLINE: Patients receive arsenic trioxide IV over 2 hours on days 1-15 OR on days 1-5, 8-12, and 15-19. Courses repeat with 2 to 5 week intervals between courses for 10-12 courses (about 1 year) in the absence of disease progression or unacceptable toxicity. Patients are followed every 3 months for 1 year, every 6 months for the second year, and then annually thereafter.