Greater difficulty exists in finding matched, unrelated donors for nonwhite patients who are candidates for hematopoietic cell transplantation (HCT). This study from researchers at the Moffitt Cancer Center and colleagues was published in Bone Marrow Transplantation.

Finding cell donors who are closely matched genetically determines the success of HCT. As the degree of mismatching increases, the success of unrelated donor HCT falls accordingly. A genetically matched sibling is the ideal donor for a patient. Searching for a perfectly matched donor takes time and affects the progress of the patient to transplantation. The genetically matched donor rate, as estimated by the National Marrow Donor Program, is 90% for white patients, 70% for Hispanics and Asians, and 60% for those of African ancestry.

“Using unrelated adult donors to facilitate HCT has provided major opportunities for patients without a matched sibling donor. In fact, the rate of unrelated donors now exceeds the rate of related donor HCT,” said Joseph Pidala, MD, MS, assistant member of Moffitt’s Blood & Marrow Transplant Department and a member of the Immunology Program. “Using data available at Moffitt, we sought to describe the determinants of a successful, unrelated donor search and to explore the contribution of donor identification versus patient characteristics leading to successful transplantation outcome.”

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The researchers sought to understand modifiable factors that limit access to unrelated donor HCT.  Unrelated donor HCT allows many patients to achieve prolonged, condition-free survival.

The researchers found that the difficulties in finding well-matched donors in some minorities was likely related to the degree of genetic heterogeneity within those groups, along with their underrepresentation in donor pools. When compared with whites, African Americans, Hispanics, and Native Americans have greater difficulty in finding a suitably matched unrelated donor, and they have less likelihood of successfully reaching HCT. Age and disease progression were also identified as barriers to HCT.

“This research speaks to the need for reducing the time from HCT consultation to donor identification and HCT,” Pidala said. “Survival benefit for HCT is dependent upon finding a suitable donor in a timely manner and addressing modifiable barriers to reaching HCT.”

“Our data are consistent with the expectation that if suitable unrelated donors could be more expeditiously identified, patient outcomes would improve, particularly for racial and ethnic minorities and for patients with better performance status,” concluded Pidala and his colleagues. “Increased representation of ethnic minorities within unrelated donor registries will increase the likelihood of finding a suitable donor.”