High-dose chemotherapy for breast cancer.

What can we conclude and hope to see in the next few years? Laboratory studies and imperfect retrospective analysis of conventional chemotherapy have created a climate of active interest to experiment with dose-intensive chemotherapy. There seems to be a consensus in favour of combination alkylating agents to maximise anticancer and rescuable antimarrow stem cell effects, whilst producing sublethal second-organ toxicity. PBPC has replaced ABMT as the routine rescue technique, on grounds of cost and recovery time. The mature results of this changed technology for support have yet to be seen in terms of the risks of late, poor engraftment and the potential benefits in terms of acute complications (faster engraftment) and tumour kill (reduced tumour contamination?). Whilst experiments continue to examine the impact of tumour contamination of blood harvests or BM harvests, inadequate attention has been paid in metastatic disease to patient selection. There seems to be a continuing growth of interest in multiple high-dose therapy regimens using stem cells collected earlier in the therapy to rescue sequential myeloablative treatments. This possibility has been realised by the stem cell technology and is being pursued with enthusiasm and with promising early results. Media-driven public interest in this increasingly political disease is pushing us to 'do more'. In future years, our worst nightmares may be realised if this means aping the experience of Halsted's disciples, "don't test, just believe"--the economic and human costs of high-dose treatment cannot justify our avoiding the rigorous examination of controlled trials.