After the chemotherapy and radiation have been completely metabolized by the body, the preserved or donated marrow is given to the patient via a transfusion. If all goes well, the stem cells in the transplanted bone marrow will give birth to a generation of tumor-free blood cells in about 15 to 25 days. A stem cell transplant is, in essence, a bone marrow transplant with several distinct differences. In a stem cell transplant, they are harvested from the circulating bloodstream. Stem cells taken from the bloodstream multiply much faster, so new cells form within only five to 15 days.
Hospital stays, if needed at all, are shorter, and costs are significantly reduced.
To stimulate stem cells to move into the bloodstream, a patient is given chemotherapy and a growth hormone for 10 to 14 days, or a growth hormone alone for five days. He or she then goes through an almost painless harvesting procedure known as leukophoresis. It is done on an outpatient basis, in a special stem cell laboratory, and is much like getting a blood transfusion. A needle is inserted into a vein and blood is slowly removed and run through a leukophoresis machine. The stem cells are filtered out, counted, and the remaining blood is pumped back into the patient.