Blood or Bone Marrow Better for Stem Cell Transplants?

Study found no survival differences, but blood cells may be associated with more chronic side effects

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By Barbara Bronson Gray
HealthDay Reporter

WEDNESDAY, Oct. 17 (HealthDay News) -- For people whose bone marrow has been destroyed by chemotherapy, radiation or disease, stem cell transplants offer a potential lifeline back to health.

But a key question has remained unanswered: Is it better to get the stem cells from a donor's blood or from bone marrow?

Now, a new study evaluates the pros and cons of harvesting stem cells from bone marrow rather than blood and suggests there are benefits to both approaches, but no survival differences between the two methods. The research was published Oct. 18 in the New England Journal of Medicine.

The study found that while peripheral blood stem cells may reduce the risk of graft failure, bone marrow may cut the chances of developing chronic graft-versus-host disease (GVHD), a complication that is frequently debilitating.

Over the past 10 years, 75 percent of stem cell transplants from unrelated adult donors have used peripheral blood stem cells rather than those harvested from bone marrow, according to study background information.

Some studies have suggested that using peripheral blood cells rather than bone marrow was associated with more severe GVHD. Other research has found that some people with transplants from peripheral blood stem cells had a lower relapse rate and improved survival.

Bone marrow offers the same chances of survival as does peripheral blood but tends to be associated with more severe side effects of treatment, explained study author Dr. Claudio Anasetti, a professor of medicine at the University of South Florida.

"With bone marrow, you have the same survival, but less long-term morbidity," Anasetti said.

Anasetti said the research shows that both approaches are acceptable, but "it's not a one-choice-for-all situation."

In some diseases, the blood-forming stem cells in the bone marrow stop working effectively and fail to generate enough new blood cells, or the right types of cells.

In other cases, people who have had had high doses of radiation or chemotherapy to destroy life-threatening cancer cells, the treatment can stop their bone marrow's ability to make blood cells.

Stem cell transplants allow physicians to replace the body's source of blood cells after the bone marrow and its stem cells have been destroyed.

GVHD is a common side effect among those who receive cells from an unrelated donor. Transplanted cells attack the patient's tissue, causing a range of issues, from skin rashes and diarrhea to serious liver problems. Chronic GVHD typically occurs between three months to three years after the transplant.

Dr. Fred Appelbaum, director of the clinical research division at the Fred Hutchinson Cancer Research Center in Seattle, argued in an accompanying editorial that adult stem cells harvested from bone marrow rather than blood should be the norm.

"If the donor and recipient are not identical twins, the graft attacks its new host. We give immune suppression to reduce this response," Appelbaum said in an interview. "But for those who get peripheral blood, there's a higher incidence of a severe, chronic immune response that can greatly diminish a person's quality of life."

For the last decade, peripheral blood has grown in popularity as a source of adult stem cells for transplant because they are easier to obtain from the donor and can be stimulated to rapidly grow even before harvesting. They also tend to establish themselves quickly inside the recipient's body.

Would more emphasis on doing bone marrow transplant rather than blood donation potentially reduce the donor pool? Appelbaum said while bone marrow donation sounds much more arduous than does blood donation, in reality they both involve a comparable level of commitment.

Donating stem cells from bone marrow usually involves receiving general anesthesia for removal of the marrow from the hip bone by needle. The process of donating peripheral blood stem cells includes taking medication -- granulocyte colony-stimulating factor or GCSF -- for four or five days, which typically causes five days of slowly building bone and muscle pain, explained Appelbaum.