PURPOSE: The benefit of consolidation high-dose chemotherapy (HDC) for high-risk primary breast cancer is controversial. We evaluated the efficacy and safety of consolidation HDC with cyclophosphamide, thiotepa and carboplatin (CTCb) followed by autologous stem-cell transplantation (ASCT) in resected breast cancer patients with 10 or more positive lymph nodes. MATERIALS AND METHODS: Between December 1994 and April 2000, 22 patients were enrolled. All patients received 2 to 6 cycles of adjuvant chemotherapy after surgery for breast cancer. The HDC regimen consisted of cyclophosphamide 1, 500 mg/m2/day, thiotepa 125 mg/m2/day and carboplatin 200 mg/m2/day intravenous for 4 consecutive days. RESULTS: With a median follow-up of 58 months, 11 patients recurred and died. The median disease-free survival (DFS) and median overall survival (OS) were 49 and 69 months, respectively. The 5-year DFS and OS rates were 50% and 58%, respectively. The 12 patients with 10 to 18 involved nodes had better 5-year DFS (67%) and OS (75%) than 10 patients with more than 18 involved nodes (30% and 38%, respectively). The most common grade 3 or 4 nonhematologic toxicity was diarrhea, which occurred in 5 patients (23%). No treatment-related death was observed. CONCLUSION: Consolidation HDC with CTCb followed by ASCT for resected breast cancer with more than 10 positive nodes had an acceptable toxicity but does not show promising survival.