Age No Longer Should Be A Barrier To Stem Cell Transplantation For Older Patients With Blood Cancers

Age alone no longer should be considered a defining factor when determining whether an older patient with blood cancer is a candidate for stem cell transplantation. That's the conclusion of the first study summarizing long-term outcomes from a series of prospective clinical trials of patients age 60 and over who were treated with the mini-transplant, a "kinder, gentler" form of allogeneic (donor cell) stem cell transplantation developed at Fred Hutchinson Cancer Research Center. The findings are published Nov. 2 in JAMA, The Journal of the American Medical Association.

"Age is no longer a barrier to allogeneic transplant," said Mohamed Sorror, M.D., M.Sc., an assistant member of the Hutchinson Center's Clinical Research Division and corresponding author of the paper.

Sorror and colleagues found that the five-year rates of overall and disease-progression-free survival among mini-transplant patients were 35 percent and 32 percent, respectively. Patients in three age groups 60 to 64, 65 to 69 and 70 to 75 had comparable survival rates, which suggested that age played a limited role in how patients tolerate the mini-transplant. Increased medical problems unrelated to cancer (comorbidities) and a higher degree of cancer aggressiveness were the two factors that affected survival among those older patients. For example, patients who had less-aggressive cancer and fewer comorbidities had a five-year survival rate of 69 percent, while patients with more aggressive cancer and a significant number of comorbidities had a survival rate of 23 percent, regardless of age.

Although a long-term survival rate of one-third of patients may seem low, these patients all would have died of their diseases within a matter of months without a transplant. "The majority of patients were referred for a transplant after they had exhausted all forms of conventional therapy," said Sorror, who works in the research group led by Rainer Storb, M.D., who developed the mini-transplant.

"While there is much room for improvement, particularly with regard to relapse, these results are encouraging given the poor outcomes with non-transplantation treatments, especially for patients with high-risk AML (acute myeloid leukemia), fludarabine-refractory CLL (chronic lymphocytic leukemia) or progressive lymphoma," the authors wrote.

The mini-transplant, known in medical circles as nonmyeloablative transplantation, was developed by researchers at the Hutchinson Center for older and medically sicker patients who otherwise could not tolerate the standard, more-toxic, high-dose regimens used to prepare patients for transplantation.