If patients with acute leukemia are transplanted with two units of umbilical cord blood (UCB), their risk of the disease recurrence is greatly reduced, finds a new study from the Masonic Cancer Center, University of Minnesota.
The finding could change the current medical practice of using one unit of UCB for treatment of patients who are at high risk for recurrence of leukemia and other cancers of the blood and bone marrow.
In the breakthrough study, Dr. Michael Verneris and Dr. John Wagner studied 177 patients treated at the University of Minnesota Medical Center, Fairview and the University of Minnesota Amplatz Children's Hospital between 1994 and 2008.
The average age of the patients in this study was 16 years. Eighty-eight patients had acute lymphoblastic leukemia (ALL) and 89 had acute myeloid leukemia (AML).
"Our analysis showed that patients in first or second remission from leukemia had a significantly lower likelihood of leukemia recurrence if they were transplanted with two UCB units than if they were transplanted with one (19 percent vs. 34 percent)," said Verneris.
"We believe our finding provides evidence that using two units of UCB for transplantation may be more effective in preventing leukemia relapse and gives hope to patients with hematological malignancies so that they may live cancer-free," he said.
The practice of using two UCB units (from two different individuals) was pioneered at the University of Minnesota approximately 10 years ago.
By using two UCB units, nearly all patients can now use this stem cell source for transplantation.
Previous research studies have also shown that about 25 to 30 percent of patients suffer leukemia relapse after transplant. The relapse or disease recurrence rates are similar regardless of whether the stem cells used for transplantation are from bone marrow, peripheral blood, or umbilical cord blood.
The researchers compared the outcomes of patients who were transplanted with one versus two UCB units.
"Given that adult patients were more likely to receive two UCB units and that they tend to have more aggressive leukemia, we think that the lower relapse rates with two UCB units is remarkable," said Verneris.
"We now know that without this double transplantation procedure, the majority of the patients treated would have had no other reasonable treatment option for their leukemia. The fact that they had less leukemia relapse was a wonderful surprise," he added.
The results are published in the current issue of the scientific medical journal Blood.