High dose chemotherapy in the treatment of breast cancer

Dose is a critical determinant of the efficacy of chemotherapy. The dose response curve for virtually all anticancer agents is steep, in both in vitro and it vivo experimental studies. However, the application of the steep dose-response curve in the clinic has been troublesome for many years because of dose limiting bone marrow toxicity. Hematopoietic support with growth factors and/or peripheral stem cell transplantation now offers new possibilities to push doses up to levels where non-myeloid toxicity becomes dose limiting. Several trials applying high dose chemotherapy with stem cell support have been conducted in breast cancer. They showed a higher response rate and a higher percentage complete remissions compared with conventional treatment. Follow-up is short for most studies but some long-term complete remissions are reported. Developments in this field are reviewed.