High-dose chemotherapy involves the use of dose-intensive chemotherapy with or without radiation followed by rescue with hematopoietic stem cells and is predicated on the concept that there is a dose-response relationship for a specific regimen in certain tumors. This modality is used in hematologic malignancies (e.g., leukemia, lymphoma, myeloma), and also where high-dose chemotherapy has proven helpful in some solid malignancies (e.g., relapsed germ cell cancer) where hematologic toxicity would prevent curative doses to be administered. Stem cell source can be peripheral blood or directly from the bone marrow. Different sources of donor stem cells can be used and silent features of each are described.
High-Dose Chemotherapy And Stem Cell Transplantation
Allogeneic bone marrow transplantation.
Allogeneic bone marrow transplantation involves obtaining the stem cells from a donor who has some human leukocyte antigen (HLA)-match with the patient. This can include matched related donor (e.g., sibling), matched unrelated donor (e.g., HLA-matched donor from the bone marrow registry), stored cord blood, syngeneic (e.g., twin sibling), and haploidentical transplantation (e.g., sibling/parent who is half-matched to the patient). Complexities of allogeneic bone marrow transplantation involve immunosuppression after the transplant to prevent rejection of the donor cells by the host. This milieu of intense cytotoxic damage to the bone marrow and immunosuppression allows the donor graft cells to launch a response against the recipient termed as graft-vs-host disease (GVHD). GVHD can also have a positive effect on the tumor by having a graft vs tumor effect, which can be curative in some malignancies like chronic myelogenous leukemia. Advantages of allogeneic bone marrow transplantation include the graft-vs-tumor effect, curative option in patients with tumor involvement of the bone marrow, and no tumor contamination of the graft cells. Disadvantages include GVHD, higher treatment-related mortality, higher infectious complications secondary to immunosuppression needed after transplant, and the need to locate a suitable donor.
Autologous bone marrow transplantation.
Autologous bone marrow transplantation uses the patient’s own hematopoietic stem cells, which are harvested and cryopreserved before treatment initiation. After the completion of high-dose chemotherapy and/or radiation, this is then reinfused. Advantages include no immunosuppressive therapy needed after infusion of stem cells, no GVHD, can be used for older patients, no donor needed, and lower treatment related mortality of about 2 to 5%. Disadvantages are that there is no graft vs tumor effect, and it also cannot be used effectively if there is involvement of the stem cells with the malignancy.