PURPOSE: The benefit of high-dose chemotherapy (HDC) for metastatic breast cancer (MBC) is controversial. We evaluated the efficacy and safety of HDC with cyclophosphamide, thiotepa, and carboplatin (CTCb) followed by autologous stem-cell transplantation (ASCT) for MBC patients. MATERIALS AND METHODS: From September 1994 to December 1999, 23 MBC patients were enrolled. All the patients received 2 to 10 cycles of induction chemotherapy. Before transplantation, 12 patients were in complete response (CR), nine were in partial response (PR), and two had progressive disease (PD). The HDC regimen consisted of cyclophosphamide 1, 500 mg/m2/day, thiotepa 125 mg/m2/day and carboplatin 200 mg/m2/day intravenously for 4 consecutive days RESULTS: After ASCT, 13 patients (56%) had a CR, five (22%) had a PR, three (13%) had no change, while two (9%) showed a PD. Seventeen patients relapsed or progressed during the median follow-up of 78 months. The median progression-free survival (PFS) time was 11 months and the median overall survival (OS) time was 23 months. The 5-year PFS and OS rates were 22% and 25%, respectively. On the multivariate analyses, less than 4 involved lymph nodes was predictive of a better PFS and OS. CONCLUSION: HDC with CTCb for MBC has acceptable toxicity; however, this treatment does not show a survival benefit.