Adjuvant high-dose chemotherapy with autologous hematopoietic stem cell support for high-risk primary breast cancer: results from the Italian national registry

The efficacy of high-dose chemotherapy (HDC) and autologous hemopoietic progenitor cell transplantation (AHPCT) for breast cancer (BC) patients has been an area of intense controversy among the medical oncology community. The aim of this study was to assess toxicity and efficacy of this procedure in a large cohort of high-risk primary BC patients who underwent AHPCT in Italy. A total of 1183 patients receiving HDC for high-risk BC (HRBC) (>3 positive nodes) were identified in the Italian registry. The median age was 46 years, 62% of patients were premenopausal at treatment, 60.1% had endocrine-responsive tumors, and 20.7% had a human epidermal growth factor receptor 2 (HER2)-positive tumor. The median number of positive lymph nodes (LN) at surgery was 15, with 71.5% of patients having ≥ 10 positive nodes. Seventy-three percent received an alkylating agent-based HDC as a single procedure, whereas 27% received epirubicin or mitoxantrone-containing HDC, usually within a multitransplantation program. The source of stem cells was peripheral blood in the vast majority of patients. Transplantation-related mortality was .8%, whereas late cardiac and secondary tumor-related mortality were around 1%, overall. With a median follow-up of 79 months, median disease-free and overall survival (OS) in the entire population were 101 and 134 months, respectively. Subgroup analysis demonstrated that OS was significantly better in patients with endocrine-responsive tumors and in patients receiving multiple transplantation procedures. HER2 status did not affect survival probability. The size of the primary tumor and number of involved LN negatively affected OS. Adjuvant HDC with AHPCT has a low mortality rate and provides impressive long-term survival rates in patients with high-risk primary BC. Our results suggest that this treatment modality should be proposed in selected HRBC patients and further investigated in clinical trials.