The rate of survival following autologous and allogeneic hematopoietic cell transplantation may have increased among all racial and ethnic groups, but disparities may still exist among some patient groups, according to a recent study published by Khera et al in Blood Advances.
Background
Autologous hematopoietic cell transplantation uses a patient’s own stem cells to help restore the body's ability to produce normal blood cells after high doses of chemotherapy and is a common treatment modality in patients with multiple myeloma and lymphoma. Allogeneic hematopoietic cell transplantation is a potentially curative treatment in patients with life-threatening hematologic malignancies such as acute leukemias and myelodysplastic and myeloproliferative syndromes. This type of therapy involves the use of stem cells from a suitable donor.
Although previous studies have demonstrated improvements in posttransplant outcomes, they have been relatively small or have not included robust data to examine trends by racial and ethnic background.
Study Methods and Results
In the recent study, investigators used the Center for International Blood and Marrow Transplant Research—which collects data on 90% and nearly 100% of autologous and allogeneic hematopoietic cell transplantation recipients in the United States, respectively—to examine the outcomes of 145,566 non-Hispanic White, non-Hispanic Black, and Hispanic patients who underwent autologous hematopoietic cell transplantation (n = 79,904) and allogeneic hematopoietic cell transplantation (n = 65,662). The investigators included five 2-year cohorts of transplant recipients who underwent the procedures between 2009 and 2018.
“This is certainly the largest study to look at the state of the science in terms of use of transplants by racial [and] ethnic minorities, involving over 145,000 transplants over a 10-year period. We wanted to see if improvements translated proportionally for all patients,” explained lead study author Nandita Khera, MD, MPH, Professor of Medicine in the Division of Hematology/Oncology at the Mayo Clinic in Phoenix.
The investigators found that the volume of hematopoietic cell transplantation rose among all racial and ethnic groups, but grew faster among Black patients and Hispanic patients compared with non-Hispanic White patients—mirroring changes in population growth rates.
Further, survival following both autologous and allogeneic hematopoietic cell transplantation improved over time across all racial and ethnic groups. However, after adjusting for mortality risk factors such as age, treatments, disease status, and donor type; non-Hispanic Black adult and pediatric patients had a 13% and 62% higher risk of mortality, respectively, compared with non-Hispanic White patients.
“This suggests the need to better understand the reasons for these disparities through qualitative studies exploring the impact of social determinants of health on outcomes,” Dr. Khera emphasized.
Based on adjusted analyses, survival outcomes for Hispanic patients were found to be on par with those of non-Hispanic White patients, an indicator of potential progress in the hematopoietic cell transplantation.
Conclusions
“Overall, we saw that the volume of transplants and survival increased for everyone, but not at the same rate,” stressed Dr. Khera.
The investigators suggested that improvements in transplant volume could have been the result of greater awareness of transplantation, better access to donors for allogeneic hematopoietic cell transplantation, and policy changes stemming from Medicaid expansion and the Affordable Care Act.
The research didn’t include enough patients of Asian descent or mixed race and ethnicity, and only captured patients receiving transplants rather than those who never gained access.
“We are using data from [the] Surveillance, Epidemiology, and End Results Program and the U.S. Census to estimate the pool of [patients] who need a transplant and using the registry data to calculate those who actually get a transplant,” revealed senior study author Theresa Hahn, PhD, of the Roswell Park Comprehensive Cancer Center
“This study helps justify efforts for continued investments in research, training, practice, and community engagement to address the disparities in access and outcomes of these highly expensive and complex medical technologies—so that everyone can enjoy the benefits of scientific progress equally,” Dr. Khera concluded.
Disclosure: For full disclosures of the study authors, visit ashpublications.org.
