Oral estramustine phosphate and oral etoposide for the treatment of hormone-refractory prostate cancer.

AbstractBackground: The purpose of the present study was to evaluate the antitumor activity and toxicity of oral estramustine phosphate (EMP) in combination with oral etoposide in patients with hormone-refractory prostate cancer. Methods: Twenty patients with adenocarcinoma of the prostate that progressed after one or more regimens of androgen-deprivation therapy were enrolled into this trial. Oral EMP was administered twice daily, for a total daily dose of 560 mg, and oral etoposide (50 mg/bodyweight per day) was given on days 1–21 and was stopped on days 22–35. Treatment was continued until evidence of disease progression appeared or two consecutive rises in the prostate-specific antigen (PSA) value were observed. Results: Ten of 20 patients showed a decrease of 50% or greater in the PSA value from initially elevated PSA levels after therapy. The median progression-free duration and 2 year cause-specific survival rate of these 10 patients were 208 days (range 71–693 days) and 67.5%, respectively. There were no significant differences in age, pretreatment PSA value, duration from initial treatment to relapse, prior therapy or survival between patients who had a decrease of 50% or greater in PSA values after this combination therapy and those who did not. The main toxicities (≥ grade 2) were anemia, leukocytopenia, thrombocytopenia, gastrointestinal and hepatic disorders, which occurred in 40, 15, 10, 15 and 5% of patients, respectively. Conclusions: The combination of oral EMP and etoposide is considered to be a well-tolerated outpatient treatment regimen for patients with hormone-refractory prostate cancer and the therapy deserves further investigation. [ABSTRACT FROM AUTHOR]