Much ado about not...enough data: high-dose chemotherapy with autologous stem cell rescue for breast cancer.
High-dose chemotherapy with autologous bone marrow or stem cell rescue (HDC/ASCR) has been proposed as a promising treatment strategy for breast cancer. Despite the frequency with which this procedure is performed, the role of HDC/ASCR in the treatment of breast cancer remains undefined. The purpose of this review is to examine the rationale for the procedure, the research progress to date, and the limitations of available data. A literature search of Medline from January 1966 through May 1997, CancerLit from January 1983 through May 1997, and Current Contents through May 1997 identified more than 600 English language papers or abstracts on this topic. Our review focuses on the preclinical and clinical data that explore the concept of chemotherapy dose intensity and the role of dose intensity in treating breast cancer. HDC/ASCR is based on the hypothesis that high-dose chemotherapy will overcome drug resistance, eradicate metastatic disease, and increase the proportion of women with breast cancer who are "cured." To date, results from only one phase 3 trial of HDC/ASCR compared with more conventional therapy have been published. Phase 2 and some phase 3 data on HDC/ASCR in the treatment of high-risk primary breast cancer and metastatic breast cancer are discussed. However, the results are inconclusive. The completion of national and international randomized trials is urgently needed to establish definitively the role of HDC/ASCR in the treatment of breast cancer.