Diethylstilboestrol (1 mg) in the management of castration-resistant prostate cancer.

OBJECTIVE

To investigate the efficacy of diethylstilboestrol (DES) in patients with advanced prostate cancer refractory to androgen suppression.

METHODS

This retrospective study comprises 194 patients with prostate cancer treated with DES (1 mg daily) between 1976 and 2010. Study outcome parameters included demographic data, tumour characteristics, treatment history, prostate-specific antigen (PSA) responses, radiologic studies, adverse events and overall survival.

RESULTS

At initiation of oestrogen therapy the mean patient age was 69 years (range: 48-89) and the median PSA was 96 ng/ml (range: 1.9-9,500). The median duration of prior prostate cancer treatment was 29 months (range: 1-365). DES was the second-line treatment in 58 patients and the third/fourth-line therapy in 136 men. A formal (≥50%) PSA response was observed in 95 patients (48.9%) and the median time to progression (TTP) was 250 days (95% CI, 180-360) for this group. An additional 62 patients (31.9%) had a partial PSA response with a median TTP of 150 days (95% CI, 92-180). Thirty-seven patients (19.1%) did not have a PSA response and the median TTP was 90 days (95% CI, 90-97). The median overall survival from the start of oestrogen therapy for the entire cohort was 576 days (95% CI, 482-690). The median overall survival of patients who had a formal (≥50%), partial (<50%) and no PSA response was 756 (95% CI, 670-1,429), 428 (95% CI, 340-630) and 329 (95% CI, 287-510) days, respectively. Thirty-nine patients (20.1%) were still alive at the end of the study. No treatment-related deaths occurred.

CONCLUSIONS

In the age of chemotherapy this study highlights the efficacy of oestrogen therapy in castration-refractory prostate cancer. The optimal point in the therapeutic pathway at which DES should be prescribed remains to be established.