Patients with leukemia or blood-related cancers are typically treated with one of two techniques, either a bone marrow transplant, or a blood stem cell transplants. Currently, there are many studies are currently being conducted to determine which option is right for each patient type.
Past studies have shown that when blood stem cell (as opposed to bone marrow) transplants are used between HumanLeukocyte Antigen (HLA)-identical siblings, or siblings whose tissue is immunologically compatible, the engraftment process is accelerated. Engraftment is when the donated cells, in this case, blood stem cells, begin to grow and produce their own new blood cells. However, with this benefit, there can be some risk. Studies have also shown that when blood stem cell transplants are used, the risk of acute and chronic graft-versus-host-diseaese (GVHD) is increased when compared to GVHD rates experienced by patients who receive bone marrow transplants. Other studies have demonstrated that patients with high-risk leukemia experience a decreased rate of relapse and improved survival rates from of blood stem cell transplant. Because these two treatment options have varying benefits and risks depending on unique patient circumstances, ongoing research is being conducted to better understand those potential benefits and risks.
Edmund K. Waller, MD, Director of the Bone Marrow and Stem Cell Transplantation Center at Winship Cancer Institute, was a key author and researcher in a study published on October 18, 2012, in the New England Journal of Medicine that could influence whether leukemia and blood-related cancer patients receive transplants from blood stem cells or bone marrow.
The study reported on the first randomized trial comparing bone marrow with peripheral blood stem cells (PBSC) for unrelated-donor transplantation. The trial involved 48 centers enrolling 551 patients as part of the Bone Marrow and Clinical Trials Network (BMT CTN). Dr. Waller helped design the study, and his lab at Winship analyzed the cells in each type of graft as the central core lab for the trial.
The study found no significant difference in the overall survival rate at two years, and no difference in relapse rates or in acute graft-versus-host-disease (GVHD). It did, however, find a significantly higher rate of chronic GVHD among patients receiving blood stem cell transplants.
Because GVHD can be a difficult and sometimes life-threatening complication from transplants, this finding could result in patients and their physicians choosing different treatments. At the very least, this finding will generate serious discussion among leaders in the transplant field about whether bone marrow or PBSC transplantation is a better treatment option.
Chronic GVHD starts more than three months after a transplant and can severely diminish a patient’s quality of life over his or her lifetime. Dr. Waller says the study leads him to believe that since the survival rates are the same, bone marrow should be the standard for the majority of unrelated-donor transplants. Exceptions to this would be patients with life-threatening infections and patients at high risk for graft rejection.
Winship played a key role in this study and, according to Waller, is part of on-going BMT CTN studies that will help shape transplant protocols and outcomes.
“This is an outstanding example of Winship investigators leading in the resolution of major questions in cancer care,” said Fadlo R. Khuri, MD, Deputy Director of the Winship Cancer Institute, and Chair of the Department of Hematology and Medical Oncology at Emory University. “Dr. Waller and his colleagues have helped define a major question, namely, whether patients who receive grafts from unrelated donors should receive peripheral stem cells or cells from the bone marrow harvest of others. This is paradigm shifting work, and Dr. Waller and his colleagues are to be congratulated for their foresight and persistence in answering this important question.”