Bone marrow transplantation has improved greatly during the past decade. The number of bone marrow transplants performed worldwide has increased dramatically since the introduction of this therapy in the 1960s, rising tenfold in the 1980s. BMT is used to treat several kinds of leukemia, lymphoma, Hodgkin's disease, renal cell, breast and ovarian cancers, as well as nonmalignant blood disorders such as aplastic anemia.
In some cases, the patient's bone marrow must be replaced because it has been destroyed by high-dose chemotherapy; in other cases, the bone marrow itself is diseased. The stem cell bone marrow are responsible for making the red blood cells that carry oxygen, the white blood cells that fight infection and the platelets that help the blood to clot.
For many patients with acute lymphoblastic or myeloid leukemia, Hodgkin's or non-Hodgkin's lymphoma and other blood disorders, an allogeneic (or donor) bone marrow transplant from a genetically matched donor offers the only hope for a cure. The ideal donor is a genetically identical sibling. For the majority of these patients, however, there will be no sibling whose bone marrow is a suitable match since there is only a one-in-four chance that any sibling will have the same HLA-type as the patient (recipient). The next best option for those without matched siblings is transplantation from an unrelated, but HLA-matched, donor. The Cancer Center has one of the few programs in New York State approved to perform this life-saving procedure.
The Cencer Center is also one of a select group of centers nationwide to offer DNA matching of potential bone marrow donors on site, rather than sending the blood sample out for analysis. Providing this sophisticated analysis on site enables physicians to match a donor to the patient more quickly.
"Before matched unrelated donor transplants became possible, nothing could be done for many patients with these deadly diseases," said Dr. Karen Seiter, Director of the Leukemia Service and Section Head for Allogeneic Bone Marrow/Stem Cell Transplantation at the Cancer Center. "We're now able to save many of them."
Traditionally, patients receiving matched unrelated donor transplants had lower disease-free survival rates and higher mortality rates.
But improvements in techniques for HLA-matching of donors and recipients, the prevention of viral infections, and prevention of graft-versus-host disease (in which the transplanted bone marrow mounts an immune response against the recipient) have greatly increased the success of matched unrelated donor transplants. What's more, there are currently three million volunteer bone marrow and stem cell donors listed with the National Marrow Donor Programs (NMDP) national donor registry, so the odds of finding an unrelated matched donor have improved substantially.
"Because there are so many more people in the registry now, it is possible for us to find donors who are closer matches to the recipient," said Dr. Seiter. "Where we used to come up with just one or two potential donors for a particular patient, now we may get hundreds."
DNA matching helps physicians to select the best donor for each patient. For example, there may be 100 potential donors who are a six-out-of-six match for antigens, but only a few that are perfect DNA matches, Dr. Seiter said.