The chance of getting a suitable bone marrow match for transplant from a pal is about 1 in 50,000 — long odds that are mitigated by the National Marrow Registry, where the database contains needed information about 5 million people who have said they stand ready to donate marrow to a stranger.

A full sibling is a 1-in-4 chance for a match. And sometimes the patient herself is the best donor. The best donor choice, in fact, depends on why the transplant is needed and whether a potential complication could actually be a benefit.

Friends who want to help someone needing a bone marrow transplant can still contribute to their well-being, though. First, they can donate whole blood or platelets through an area blood bank, because someone needing a transplant is very likely to need blood. They can also join the registry and make their marrow available to others in need. The more people on the registry, the better the likelihood of a match for anyone who needs it. That's especially true of African-Americans and other ethnic groups that are underrepresented on the registry.

That's according to Dr. Finn Bo Petersen, medical director of the Intermountain Blood and Marrow Transplant Program at LDS Hospital, and his associate director, Dr. Julie Asch. The two were featured on Saturday's Deseret Morning News/Intermountain Healthcare Hotline.

The typing done to find a suitable match is expensive, and joining the registry is not free; Asch suggests people look for sponsored opportunities to have the typing done, perhaps during a marrow drive when an organization or individual is offering to underwrite at least some of the cost.

While the duo talked about the risks of a stem cell transplant, using either marrow or peripheral blood stem cells, they also noted the very good results that someone can get with a transplant. For many cancer patients, it provides a complete cure. For some, it is the only hope. And doctors have a whole arsenal to battle side effects and complications.

Cancer is the reason 90 percent of transplants are done, although the transplants can also resolve some genetic anomalies and may also provide hope for some autoimmune disorders like multiple sclerosis and rheumatoid arthritis. But those are relatively new uses for the transplants compared to the 30 years that bone marrow transplants have been used for cancers. The medications to control side effects — and general understanding of what happens with a transplant — have greatly improved in that time.

One of the primary complications of bone marrow transplantation is called graft vs. host disease (GVHD), in which the donor's healthy stem cells see the recipient as foreign — a kind of reverse rejection — and react, sometimes badly. Common sites for acute GVHD include the skin, stomach and liver. The good news, Petersen said, is GVHD usually burns out over time, although it can take several years. Asch said, on average, 15 percent of transplant patients are being teated for GVHD at the two-year point following the transplant.