High-Dose Chemotherapy and Autologous Hematopoietic Stem Cell Transplantation as Adjuvant Treatment in High-Risk Breast Cancer: Data from the European Group for Blood and Marrow Transplantation Registry

• The prognosis of high-risk BC patients has changed very little in the past 2 decades with the use of conventional chemotherapy.
• High-dose chemotherapy (HDC) with autologous hematopoietic stem cell transplantation (AHSCT) is today a safe treatment modality with low toxicity.
• The efficacy of HDC and AHSCT for high-risk BC has been an area of intense controversy among the medical oncology community.
• Phase II studies suggested that this approach improved long-term disease control.
• Preliminary reports from randomized studies did not showed an overall survival benefit.
• Nevertheless, HDC might be of potential benefit in subgroups of high-risk BC patients.
• As a contribution to this field, we report the results of this approach in a large cohort of high-risk BC patients treated in Europe between 1995 and 2005.

The aim of this retrospective study was to assess toxicity and efficacy of adjuvant high-dose chemotherapy (HDC) and autologous hematopoietic stem cell transplantation (AHSCT) in 583 high-risk breast cancer (BC) patients (>3 positive nodes) who were transplanted between 1995 and 2005 in Europe. All patients received surgery before transplant, and 55 patients (9.5%) received neoadjuvant treatment before surgery. Median age was 47.1 years, 57.3% of patients were premenopausal at treatment, 56.5% had endocrine-responsive tumors, 19.5% had a human epidermal growth factor receptor 2 (HER2)-negative tumor, and 72.4% had ≥10 positive lymph nodes at surgery. Seventy-nine percent received a single HDC procedure. Overall transplant-related mortality was 1.9%, at .9% between 2001 and 2005, whereas secondary tumor-related mortality was .9%. With a median follow-up of 120 months, overall survival and disease-free survival rates at 5 and 10 years in the whole population were 75% and 64% and 58% and 44%, respectively. Subgroup analysis demonstrated that rates of overall survival were significantly better in patients with endocrine-responsive tumors, <10 positive lymph nodes, and smaller tumor size. HER2 status did not affect survival probability. Adjuvant HDC with AHSCT has a low mortality rate and provides impressive long-term survival rates in patients with high-risk BC. Our results suggest that this treatment modality should be considered in selected high-risk BC patients and further investigated in clinical trials.