Introduction: current issues in high-dose chemotherapy and stem cell support

In the 1980s it became clear that low numbers of primitive hematopoietic cells were present in the peripheral bloodstream. Early clinical trials by investigators in the USA, Australia, and Germany demonstrated that these cells could be collected and reinfused to support high-dose chemotherapy procedures in patients otherwise unable to undergo bone marrow collection, usually because of prior pelvic irradiation. It was, however, difficult to obtain adequate numbers of stem cells from patients in the steady state. It was not until the demonstration by Socinski in Boston and Gianni in Milan that these circulating cells were markedly increased following the administration of either cytokines, chemotherapy, or a combination of both that the use of peripheral blood stem cells over bone marrow began to be widely undertaken. Since that time, peripheral blood stem cell collection has become the preferred means of stem cell support for high-dose chemotherapy because of the reduction in time to neutrophil and platelet engraftment, reduction in the number of transfusions and hospital stay, and an apparent reduction in tumor cell contamination.