Study Finds Big Strides Made in Treating Leukemia, Lymphoma in Past Decade
WEDNESDAY, Nov. 24 -- Clinicians have made remarkable advances in treating blood cancers with bone marrow and blood stem cell transplants in recent years, significantly reducing the risk of treatment-related complications and death, a new study shows.
Between the early 1990s and 2007, there was a 41 percent drop in the overall risk of death in an analysis of more than 2,500 patients treated at Fred Hutchinson Cancer Center in Seattle, a leader in the field of blood cancers and other malignancies.
Researchers from the Fred Hutchinson Cancer Center, who conducted the study, also noted dramatic decreases in treatment complications such as infection and organ damage.
The study was published in the Nov. 24 issue of the New England Journal of Medicine
"We have made enormous strides in understanding this very complex procedure and have yielded quite spectacular results," said study senior author Dr. George McDonald, a gastroenterologist with Hutchinson and a professor of medicine at the University of Washington, in Seattle. "This is one of the most complex procedures in medicine and we understand a lot of complications we didn't before."
Dr. Mitchell Smith, head of the lymphoma service at Fox Chase Cancer Center in Philadelphia, feels the general positive trend -- if not the exact numbers -- can be extrapolated to other care centers.
"Most of the things that they've been doing have been generally adopted by most transplant units, although you do have to be careful because they get a select patient population and they are experts," he said. "The smaller centers that don't do as many procedures may not get the exact same results, but the trend is clearly better."
Treatment of high-risk blood cancers such as leukemia, lymphoma and myeloma was revolutionized in the 1970s with the introduction of allogeneic blood or bone marrow transplantation.
Before this advance, patients with blood cancers had far more limited options. The high-dose chemotherapy or radiation treatments designed to kill blood cancer cells (which divide faster than ordinary cells) often damaged or destroyed the patient's bone marrow, leaving it unable to produce the blood cells needed to carry oxygen, fight infection and stop bleeding. Transplanting healthy stem cells from a donor into the patient's bone marrow -- if all went well -- restored its power to produce these vital blood cells.
While the therapy met with great success, it also had a lot of serious side effects, including infections, organ damage and graft-versus-host disease (GVHD), which were severe enough to prevent older and frailer patients from undergoing the procedure.
But the past 40 years has seen a lot of improvements in managing these problems.
The authors of this study compared the experiences of 1,418 patients who underwent their first allogeneic transplants at Hutchinson between 1993 and 1997 with those of 1,148 patients who had the same procedure a decade later, between 2003 and 2007.
Patients had types of leukemia, lymphoma, multiple myeloma and myelodysplastic syndrome and received peripheral-blood stem cells or bone marrow from unrelated donors. In the later period, more peripheral-blood stem cell transplantations were done and fewer bone marrow transplantations were performed.
The overall rate of death without a relapse declined 52 percent, and the overall early death rate (200 days post-procedure) without a relapse dropped 60 percent.
About 55 percent of patients undergoing transplantations in the earlier period survived a year, compared with 70 percent of those in the later period.
And there were improvements in the rates of just about every complication, even though the patients treated in 2003-2007 were older and sicker than those treated a decade earlier. For instance, the chances of developing severe graft-versus-host disease went down by 67 percent over the decade, partly thanks to better drugs. There was also less disease caused by infections and less treatment-related damage to the liver, kidney and lungs, the analysis found.
The authors can't be sure about the reasons for the improvements, but speculate that it has to do with more controlled chemotherapy doses; less toxic "conditioning" to rid the body of attack lymphocytes; better detection and prevention of viral, bacterial and fungal infections, as well as the availability of better antifungal (and other) medications as well as better matching of donors and recipients.
Use of peripheral-blood stem cells, which increased during the time frame, also is easier on the patient, they noted.
In addition, the introduction of the drug Gleevec to treat patients with chronic myeloid leukemia has eliminated the need for transplantation in these patients, Smith added.
"I think we all feel comfortable that we are doing much better than we were doing 10 years ago, particularly in terms of early deaths and preventing and managing toxicity, and a lot of it has come out of this group [the Fred Hutchinson Cancer Center]," said Smith. "They're the ones that lead the way."
Dr. Nelson Chao, head of the transplantation program and professor of medicine at Duke University in Durham, N.C., agreed that "a lot of these treatments are now standardized in many places."
McDonald and five other authors reported ties with pharmaceutical companies. The study was funded by the U.S. National Institutes of Health.
The Leukemia & Lymphoma Society has more on stem cell transplantation.
Posted: November 2010
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