High-dose therapy for breast cancer.

In recent years, the most frequent indication for high-dose autologous stem-cell-supported chemotherapy in the United States has been breast cancer. This approach is applied in "high-risk," early-stage disease as adjuvant treatment, and with either curative or palliative intent in metastatic disease. Among both lay persons and medical professionals, high-dose therapy is broadly viewed as standard and appropriate, even though the results of the largest prospective randomized studies are not yet available. This view is based on extrapolation from preclinical data, a fundamental belief that "more is better," a faith in high technology, and the results of numerous pilot and phase I and II trials. Because high-dose therapy is promising, but also more difficult to administer than standard therapy, controversy rages in all circles concerning its use. Unless and until we have the results of properly randomized, prospective studies, this controversy will likely continue. Against this background, we will review the theoretical basis for high-dose treatment in breast cancer, the translation of this laboratory science into the clinic, usual treatment approaches, the available data, ongoing clinical trials, and future research directions.