Stem Cell Transplant Should Be Considered at Diagnosis, Say Experts


In the October 2014 issue of Clinical Oncology News, hematopoietic stem cell transplant (HSCT) experts report that the growing consensus among them is that oncologists should begin the work-up necessary for HSCTs among patients with blood disorders at the earliest possible opportunity.

This runs contrary to what has thus far been the standard of care for most patients with lymphoma, leukemia and other blood diseases: when all else fails, turn to HSCT.

According to Dennis Confer, MD, chief medical officer of the National Marrow Donor Program (NMDP), "The time to think of transplant and to conduct HLA typing is at the time of diagnosis."

HLA typing (also called HLA matching) refers to the human leukocyte antigen (HLA) protein, or marker. There are many different HLA markers, all with different names, and they can be found on the surface of most of the cells in the human body. Our immune system uses the HLA markers specific to each person to determine which cells belong in that body and which do not.

When trying to find a match for a person who needs a stem cell transplant, doctors will try to find a donor who shares between 6 and 8 HLA markers with the recipient. The better the match-- meaning the more markers they share, the greater the odds that the procedure will be a success.

When the source of the donor cells is umbilical cord blood (UCB), as few as four HLA matches are necessary because UCB cells are not as mature as cells from the other sources.

Although nothing has changed regarding the criteria for the best-possible HLA-matched donor, what has changed is the definition of a 'suitable donor', says medical writer Ted Bosworth.

"Extensive data have been presented in the past year ... showing that outcomes are acceptable with 7/8 allele matches for unrelated donor blood and 4/6 allele matches for umbilical cord blood. Even if outcomes are inferior to those of an optimally matched graft, outcomes are better than those anticipated in the absence of HCT."

Dr. Confer says that patients who are eligible for an HSCT should take it if offered to them, adding that one of the few remaining limitations in this field is that "clinicians are not thinking about it soon enough."

One reason experts are recommending transplants sooner rather than later is that there is a large and ever-expanding bank of available donor cells. In the United States, a suitable donor can now be found for four out of every five patients seeking one-- a substantial gain from previous eras, when donor availability was a major obstacle for so many patients.

Experts like Dr. Confer say that at the very least, eligible patients should begin HLA matching when they are first diagnosed with cancer. The initial search is free and takes almost no time at all.

"We once thought the more chemotherapy the better," says Confer. "Now, I think the limitations of chemotherapy are better appreciated. We realize that the grafts themselves offer a significant antileukemic effect, and the opportunity to control disease with transplant may be best when it is offered promptly."

Source: Clinical Oncology News

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