Leukapheresis is a method for obtaining autologous (i.e., the patient's own) peripheral blood stem cells (PBSCs) for later transplant into the patient. Autologous PBSC transplants are being studied in clinical trials to "rescue" the immune system and blood-forming cells of breast cancer patients receiving high-dose chemotherapy.
Sometimes breast cancer becomes resistant to treatment with radiation therapy or normal doses of chemotherapy drugs. High doses of chemotherapy can destroy the immune cells in the bone marrow. Therefore, PBSCs are taken from the patient before high-dose chemotherapy treatment.
In order to obtain PBSCs, a patientís blood is passed through a machine that removes the stem cells (immature cells from which all blood cells develop) from the blood and then returns the blood back to the patient. This procedure is called leukapheresis, and the process usually takes 3 or 4 hours to complete. The PBSCs obtained by leukopheresis are treated with chemotherapy drugs in the laboratory to kill any cancer cells that might be present. Next, the treated (ďpurgedĒ) PBSCs are frozen for later use.
Very high doses of chemotherapy with or without radiation therapy may then be used to treat the breast cancer. The frozen PBSCs are then thawed and injected back into the same patient to replace the marrow that was destroyed by the chemotherapy. This type of transplant is an autologous transplant. PBSC transplantation may be done alone or with an autologous bone marrow transplant (i.e., with bone marrow cells from the patient).