Umbilical cord blood transplants may offer blood cancer patients better outcomes than bone marrow transplants, according to an analysis of outcome data performed at the Statistical Center, Center for Blood and Marrow Transplant Research (CIBMTR), Medical College of Wisconsin, Milwaukee.
This is the first large study in children to directly compare matched bone marrow, which is currently considered the preferred graft, to matched and mismatched umbilical cord blood. There is considerable controversy in the medical community about which source of blood stem cells (cord blood or marrow) should be considered the ‘gold standard' for the treatment of childhood leukemia.
In this study, the investigators compared outcomes of pediatric leukemia patients who received unrelated bone marrow transplants versus those who received umbilical cord transplants. All bone marrow donors were matched with their recipients using very sensitive methods to determine donor and recipient tissue types.
Nearly all cord blood donors were mismatched. Up until now, no study had compared cord blood to bone marrow with this degree of HLA-matching.
The main objective of this analysis was to provide guidelines to transplant physicians on the selection of the best donor for children with leukemia.
Remarkably, mismatched cord blood performed as well as matched bone marrow as measured by leukemia free survival rates as long as the degree of mismatch was limited and the number of cord blood cells available was sufficient.
Furthermore, study participants who received matched cord blood had a 20 percent higher survival rate than matched bone marrow recipients though the number of matched cord blood transplants was small.
The research appears in this week's issue of the Lancet . Mary Eapen, M.D., M.S., Associate Professor of Pediatrics at the Medical College of Wisconsin and Associate Scientific Director of the CIBMTR is the lead author. The study was done in collaboration with the National Cord Blood Program, New York Blood Center, led by Drs. Pablo Rubinstein and Cladd Stevens. John E. Wagner, M.D., Professor of Pediatrics and Director of the University of Minnesota Division of Pediatric Hematology/Oncology and Bone Marrow Transplantation and co-chair of the CIBMTR Graft Sources Working Committee is the senior investigator.
“What this study suggests is that cord blood need not be considered as a second line therapy in children with leukemia who may benefit from a transplant,” said Eapen. The fact that the cord blood is banked and readily available with little notice is a great advantage. Leukemia patients can wait months for an appropriately matched bone marrow donor, during which time their disease might return. Further, most children should be able to find either a matched bone marrow donor or a minimally mismatched cord blood unit.