Diethylstilbestrol in castration-resistant prostate cancer

What's known on the subject? and What does the study add? Diethylstilbestrol (DES) was the first hormone treatment used for prostate cancer and has also shown effectiveness in castration-resistant disease in small studies; however, concerns over thromboembolic toxicity have restricted its use in the past. Over 200 elderly men with castration-resistant prostate cancer were treated with 1-3 mg of DES, given with 75 mg aspirin and breast bud irradiation. Almost 30% of men showed a significant PSA response and the median time to PSA progression was 4.6 months. Almost 20% of patients with pain had a significant analgesic benefit. The most important toxicity was thromboembolism in 10% of men. Overall the drug has an acceptable toxicity profile and offers a palliative benefit in frail elderly men who may not be fit for chemotherapy.

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.