| Popis: |
Autologous peripheral stem-cell transplantation (APSCT) has been extensively applied to support cancer patients who have undergone high-dose chemotherapy (HDCT) and suffer from the effects of otherwise prolonged or irreversible myelosuppression. The APSCT process involves harvesting of autologous progenitor cells from a patient's circulating blood (via leukapheresis), cryopreservation of the cells, and subsequent intravenous infusion for bone marrow hematopoietic reconstitution (HR). Although pluripotent stem cells, capable of multilineage differentiation, cannot be distinguished by morphologic criteria, they can be characterized as being CD34+ cells capable of indefinite self-renewal in situ and long-term self-renewal in cell cultures. Bone marrow and peripheral blood are common sources of autologous progenitor cells. Current techniques to identify and separate CD34+ cells for use in APSCT have resulted in fewer tumor cells being infused than if unseparated peripheral stem cells (PSC) were transplanted, with no differences noted in HR. Chemotherapy- and cytokine-induced mobilization results in increases in progenitor cells, necessitating fewer phereses to harvest sufficient numbers of progenitor cells for engraftment. This assessment addresses the safety, efficacy, and cost-effectiveness of the use of PSC for HR and improving patient outcome, as well as the indications and criteria for patient selection for the use of APSCT. Available information from study panels, research centers, institutions, and government agencies is reviewed; randomized clinical tests (or lack thereof) are discussed; and comparisons are made between APSCT and autologous bone marrow transplantation (ABMT), an accepted therapy in treatment of some malignancies (e.g., leukemia and lymphoma). The author concludes that existing evidence indicates that PSC can provide satisfactory HR, and the rate of HR via PSC does not seem consistently different from that of ABMT. The clinical importance of HR continues to be secondary to the primary issue of the patient benefits of HDCT in terms of antitumor response, palliation, or survival. |
