A Comparison of Hydroxyurea, Methyl-chloroethyl-cyclohexy-nitrosourea and Cyclophosphamide in Patients with Advanced Carcinoma of the Prostate

This is the fifth completed randomized clinical trial of the National Prostatic Cancer Project. There were 125 patients with histologically confirmed relapsing clinical stage D prostatic cancer randomized to receive hydroxyurea, methyl-chloroethyl-cyclohexy-nitrosourea or cyclophosphamide. All patients had received and failed previous hormonal therapy. Patients whose disease progressed after 12 weeks on the initial therapy were crossed over or randomized to receive an alternate drug. There were 98 patients available for comparison of treatments. Objective responses included patients with complete or partial regression as well as stable disease. The response rates were 35 per cent for cyclophosphamide, 30 per cent for methyl-chloroethyl-cyclohexy-nitrosourea and 15 per cent for hydroxyurea. Subjective response parameters included improvement in performance status and relief of pain. Pain was improved in a fifth of the patients on each treatment area. Methyl-chloroethyl-cyclohexy-nitrosourea and hydroxyurea showed activity in advanced prostatic cancer patients but at the expense of excessive toxicity. Cyclophosphamide continues to be the most active single agent in this type of patient, particularly with regard to duration of response and survival. There was a statistically demonstrable advantage for cyclophosphamide over hydroxyurea and a marginal advantage over methyl-chloroethyl-cyclohexy-nitrosourea in survival experience.