Diethylstilbestrol in castration-resistant prostate cancer

OBJECTIVE To assess the efficacy and toxicity of diethylstilbestrol (DES) in the management of castration-resistant prostate cancer (CRPC). PATIENTS AND METHODS A total of 231 patients with CRPC received treatment with DES at the Royal Marsden Hospital between August 1992 and August 2000. The median pre-treatment prostate-specific antigen (PSA) level was 221 ng/mL. DES was used at a dose of 1-3 mg daily, with aspirin 75 mg. The primary endpoint was PSA response rate. RESULTS The PSA response rate (using PSA Working Group criteria) was 28.9%. The median time to PSA progression was 4.6 months. Of patients with bone pain, 18% had an improvement in their European Organisation for the Research and Treatment of Cancer pain score. Thromboembolic complications were seen in 9.9% of all patients. CONCLUSIONS DES has significant activity in CRPC and can be of palliative benefit. DES has an acceptable toxicity profile in the management of patients with symptomatic CRPC when used at a dose of 1-3 mg, combined with aspirin and prophylactic breast bud radiotherapy.