Autologous stem cell transplantation in breast cancer

High-dose chemotherapy with autologous stem cell support is an investigational treatment for patients with breast cancer who have a high risk of recurrence or who have metastatic disease. In the adjuvant setting, there is a lack of survival data from randomized studies comparing high-dose to conventional-dose therapy. High-dose adjuvant chemotherapy was found to result in as high as 71% 5-year event-free survival in patients with more than nine metastatic axillary lymph nodes in one nonrandomized study, which appears to be superior to those achieved with conventional-dose therapy. In metastatic breast cancer the great majority of patients die of cancer despite high-dose therapy with the current regimens, and it is unclear whether survival of these patients is improved with high-dose therapy as compared to conventional-dose therapy. However, a few patients with breast cancer with distant metastases have enjoyed a disease-free interval lasting for several years after high-dose therapy, which is rarely seen with conventional-dose therapy, and one small randomized trial showed improved survival in the high-dose arm of the study. The more extensive patient selection for high-dose chemotherapy needs to be taken into account when comparing the results achieved with different dose levels, and therefore a high priority should be given for randomized studies where high-dose therapy is compared with conventional-dose therapy.