OUTLINE: This is a randomized, double blind, multicenter study. Patients are randomized to one of three treatment arms. Arm I-II: Patients receive one of two different doses of oral eflornithine daily. Arm III: Patients receive oral placebo daily. Treatment continues for 28 days in the absence of disease progression or unacceptable toxicity. Patients are followed at 28 days, and then at 6, 12, 18, and 24 months.