Allogeneic bone marrow transplantation—which involves giving the child who has cancer bone marrow taken from a donor, ideally a close relative such as a brother or a sister—is being used very often in children with acute non-lymphoblastic (granulocytic) leukemia. It is also used quite frequently in children with acute lymphoblastic leukemia who have had a relapse.
In autologous bone marrow transplantation, the patient's own bone marrow is used. A portion of the bone marrow is stored in the laboratory while the patient receives treatment, and then returned in the form of an intravenous infusion of bone marrow cells . These cells circulate throughout the body and settle into the bone marrow compartment from which they came. They subsequently grow and regenerate the bone marrow. For some children who do not have a matched close relative, marrow donors may be sought through a registry of volunteers whose marrow type is known and who may donate their marrow. Such transplants, known as matched unrelated donor transplants (MUDs), may have a higher complication rate.
Newer approaches have also recently been devised. It is now known that bone marrow cells may circulate throughout the blood, and machines that can remove some of the circulating cells are being developed, raising the possibility of removing bone marrow cells from a vein rather than by drawing them out of bones through a needle.
In high-dose rescue therapy—also known as autologous rescue—the patient's bone marrow cells are stored while high-dose chemotherapy is given. The cells are then reinfused. The higher doses of chemotherapy may kill cancer cells more effectively but might also seriously damage the bone marrow if rescue therapy was not performed.
