Docetaxel was the first chemotherapy to demonstrate improvement in survival in patients with mCRPC. In the TAX 327 study, patients received 5 mg of prednisone twice daily and were randomly assigned to receive 12 mg of mitoxantrone per square metre of body-surface area every 3 weeks, 75 mg of docetaxel per square metre every 3 weeks, or 30 mg of docetaxel per square metre weekly for 5 of every 6 weeks.17The median survival was 16.5 months in the mitoxantrone group, 18.9 months in the group given docetaxel every 3 weeks, and 17.4 months in the group given weekly docetaxel. As compared with the survival rate in the mitoxantrone group, the survival rate was significantly higher (P = 0.009) in the group given docetaxel every 3 weeks but not in the group given weekly docetaxel (P = 0.36). With an extended follow-up that included death of 86% of the patients, the 3-year survival rates were higher in those treated with the 2 docetaxel schedules (18.6 and 16.6 vs 13.5% with mitoxantrone, respectively).18Apart from cardiac events, which were more frequent in the mitoxantrone group, other adverse events were more frequent among patients receiving docetaxel, and there was no trend toward a lower frequency with weekly docetaxel than with docetaxel given every 3 weeks. The addition of estramustine to docetaxel has been shown to increase side effects without enhancing efficacy.19
A retrospective study of 89 patients with castrate-resistant prostate cancer treated at the National Cancer Centre Singapore evaluated the efficacy and tolerability of 2 attenuated regimens60 mg of docetaxel per square metre every 3 weeks, and weekly docetaxel (20 to 35 mg per square metre) (unpublished data). The use of 60 mg of docetaxel per square metre every 3 weeks had similar efficacy and an acceptable toxicity profile compared to the standard 75 mg of docetaxel per square metre every 3 weeks. Weekly docetaxel had significant palliative benefits among symptomatic patients despite lower overall survival.