Those were the findings of a study conducted for the International Bone Marrow Transplant Registry by an international group of scientists and published in a recent issue of The New England Journal of Medicine. The study focused on allogeneic transplants, which involve transplanting marrow from one person to another of similar genetic makeup, said Ralph Vogler, MD, scientific program director at the American Cancer Society (ACS).

The study included 6,691 patients who were disease-free two years after having a bone marrow transplant to treat leukemia or aplastic anemia, a condition in which production of blood cells by the bone marrow is severely reduced. The patients had an 89 percent chance of living for five more years, the researchers found.

In this study and another study by the European Group for Blood and Marrow Transplantation, the death rate for patients who survived for five years after a transplant was about 8 percent – a rate that is higher than that of the general population. However, patients who had transplants to treat aplastic anemia had a lower probability of late death than those who had transplants to treat leukemia.

The researchers said their results should be interpreted with caution because protocols for transplantation, treatment of complications, and follow-up were not uniform among patients in the study. In addition, they said transplantation techniques have changed over the three decades since the first patients were enrolled in the international registry.

The authors recommended prolonged follow-up of patients who receive transplants to prevent and treat life-threatening complications or relapse.

Dr. Vogler agreed, saying, "Long-term follow-up is important because we do not know enough as yet. The significance of this study is that it demonstrates a decrease in life span even though the patients may be cured of their original disease…It will take further investigation to determine what factors are responsible for increasing the risk of death."

E. Donnall Thomas, MD, of Fred Hutchinson Cancer Research Center, wrote an editorial accompanying the study. "It is clear that marrow transplantation does not confer a normal life span.  However, the slightly increased risk of death with the passage of years may not be so bad when one considers the alternative," wrote Dr. Thomas, a Nobel Prize winner who is a pioneer in the procedure.

Although high-dose chemotherapy and bone marrow transplantation offer many leukemia patients the best opportunity for long-term survival, a transplant is not a good choice for everyone. Some types of leukemia respond very well to conventional chemotherapy, and a transplant is not necessary. And, the complication rate after a transplant is quite significant, especially for older patients and those with other serious health problems. Many previous studies have been done to determine which people with leukemia are likely to benefit from a bone marrow transplant.