OUTLINE: All patients remain on a reduced calcium diet for the duration of the study. Twelve hours prior to treatment, patients begin drinking 4-6 glasses of extra fluid for 3 days. Patients receive oral calcitriol over 4 hours weekly. Treatment continues in the absence of disease progression or unacceptable toxicity. Quality of life is assessed at baseline, every 4 weeks during treatment, and at the end of the study. Patients are followed for at least 1 month.