February 9, 2015

The amount of blood collected from the umbilical cord following birth is a small, but efficient amount. Some parents may wonder if it is enough to be effective should it ever be needed for their child. Though it doesn’t seem like much – the average amount collected is approximately 2 ounces – that little bit of blood and the number of stem cells it contains can pack quite a punch, in the healing process.

When it comes to cord blood transplants, one might reason that more units of cord blood stem cells means better results. That line of thinking used to be the norm in the transplant community actually, but a recent study has proven otherwise. According to a study conducted by the Bone and Marrow Transplant Clinical Trials Network in 2012, children with blood cancers who were treated with cord blood transplants showed similar outcomes and survival rates whether they received one or two units of blood1.

The phase III study was conducted at the University of Minnesota Medical School over the course of five years and its purpose was to determine whether patients showed a higher success rate when given a double cord blood transplant as part of their treatment. Those taking part in the study ranged in age from 1 to 21 years and had varying ranges in the severity of their cancers (which included acute leukemia, chronic myeloid leukemia, or myelodysplasia syndrome). Half of the 224 adolescents taking part in this clinical trial were given a single cord blood unit, the other half received a double unit treatment. Prior to the transplants, all the patients underwent treatments (of chemotherapy and/or radiation) to kill the cancer cells, as well as receiving a medication to help prevent the development of Graft vs. Host Disease (GVHD).

The results of the study were surprising. One year post-transplant, the survival rates of those involved in the study were 65 percent for double-unit recipients and 73 percent for single-unit recipients. A single unit transplant also showed a slight advantage in the reoccurrence of the diseases; those staying disease-free during that same one-year timeframe were 64 percent for double units, 70 percent for single unit.

Another potential benefit of single-unit treatments also emerged in the study regarding those who developed GVHD, though the rate of occurrence in either category was low and the difference was minimal.

The researchers who conducted these clinical trials point out that this is great news when it comes to the treatments of these blood disorders. It means that if a family banks their child’s cord blood, that one unit alone could be all the child needs for the successful treatment of certain diseases. It also means that families who have not stored their children’s cord blood and must rely on a donor would only need to seek out one matching cord blood donation, as opposed to two. Finding one good genetic match is a difficult undertaking in itself, but finding two is even more challenging.

  • One-Unit versus Two-Unit Cord-Blood Transplantation for Hematologic Cancers. Wagner, Jr., John E., M.D., N Engl J Med 2014; 371:1685-1694 DOI: 10.1056/NEJMoa1405584. Published October 30, 2014. Found online http://goo.gl/qU5H1L
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