Docetaxel with or without estramustine for estramustine refractory castration-resistant prostate cancer: a single institution experience

To compare the efficacy and toxicity of DTX and EMP, we divided CRPC patients, who were confirmed to be resistant to EMP, into the following two groups: group D (n = 28), which included patients treated with DTX (60 mg/m2, once in every four weeks) alone, and group DE (n = 33), which included patients treated with a combination of DTX (60 mg/m2, once in every four weeks) and EMP (twice daily oral administration at 280 mg).Prostate specific antigen (PSA) response (> 50% decline in PSA) was observed in six patients (21%) in group D and eight patients (24%) in group DE. The median time to progression (TTP) was 12.0 months and 6.2 months and the median overall survival (OS) was 26.4 months and 24.3 months in group D and DE, respectively. There was no statistical difference between the two groups in terms of PSA response, TTP, and OS. The incidence of adverse events of grade 3/4 was low in both the groups, and there was no statistical difference between the two groups.Although treatment with DTX at 60 mg/m2 was effective and highly tolerated in EMP-refractory Japanese CRPC patients, the DTX and EMP combination therapy might not exhibit any survival benefit for CRPC patients.The efficacy of docetaxel (DTX) in castration-resistant prostate cancer (CRPC) patients was shown in two clinical trials of TAX 327 [1] and SWOG 9916 [2] in 2004. Thereafter, DTX-based therapies have been used worldwide for treating CRPC patients. TAX 327 reported a median overall survival (OS) of 18.9 months with administration of DTX every three weeks, and SWOG 9916 reported a median OS of 17.5 months with DTX and estramustine phosphate (EMP) combination therapy every three weeks. While these results showed that DTX was more effective than mitoxantrone, they also raised other questions about whether addition of EMP to DTX was effective for CRPC patients. To clarify this point, several clinical trials and one meta-analysis have been performed thus far. While there have been some reports describing th