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

We evaluated the efficacy and toxicity of oral estramustine phosphate (EMP) and oral etoposide (VP-16) in patients with hormone-refractory prostate cancer (HRPC). Eleven patients with metastatic HRPC were treated with oral EMP 420 mg/day and oral VP-16 50 mg/day for 21 days, followed by discontinuance of treatment for 7 days, and the cycle was then repeated. The cycle of treatment was continued until evidence of disease progression or unacceptable toxicity was observed. Five of 11 patients (45%) demonstrated a 50% decrease or more in pretreatment prostate-specific antigen (PSA) levels (responders). The median survival time was 12 months and the 1-year overall survival rate was 61.4% in all patients. The median survival time of responders was 13 months, which was significantly longer than non-responders. There was no significant difference between responders and non-responders in age, pretreatment PSA value or duration from initial treatment to relapse. The main toxicities were anemia, leukocytopenia and thrombocytopenia, which were observed in 27, 27 and 8% of patients, respectively. We conclude that the combination of oral EMP and oral VP-16 is an active and well-tolerated oral regimen in HRPC.