The efficacy and tolerability of docetaxel 100 mg/m(2) every 3 weeks as second-line chemotherapy in patients with metastatic breast cancer was investigated. In addition, the efficacy of a 3-day prophylaxis against cumulative dose-related fluid retention was examined with methylprednisolone 32 mg twice daily for 3 days starting 12 and 3 h before the docetaxel infusion together with oral cetirizine 10 mg 12 and 3 h before start of docetaxel for prevention of acute hypersensitivity reactions. According to the intent to treat-analysis 35% (95%CI: 25; 46) of the 94 patients entered responded to therapy. Their median survival was 12 months (range 0-20 months). The respective response rate for the 87 patients eligible for response evaluation was 37% (95%CI: 27; 48). Their median duration of response was 8 months (range 3-12 months), their median time to progression was 4 months (range 1-12 months). The corresponding response rate in the eligible patient cohort with anthracycline-resistant disease was 28% (95%CI: 15; 45) and increased to 44% (95%CI: 30; 59) in the cohort with non-anthracycline-resistant disease. Patients with visceral metastases responded in 36% and patients with > or = 3 organs involved in 33%. In a retrospective analysis, the 3-day premedication of corticosteroids and antihistamines proved to be as effective as the established but more toxic 5-day regimen in delaying and preventing the occurrence of docetaxel derived toxicities especially the cumulative fluid retention. In conclusion, docetaxel represents one of the most active agents for second-line treatment of metastatic breast cancer, especially for anthracycline-resistant patients. Due to comparable effectiveness of the 5-day regimen which is widely used by others and the 3-day premedication tested in this trial the latter proved to be more favourable and was therefore recommended for future therapies.