Working together for children with cancer

March 10, 2009
Sickle cell services expand

Doctors at Dana-Farber and Children's Hospital Boston have joined colleagues at other hospitals in developing a new treatment option for people with sickle cell disease while ensuring that patients and their families are aware of the full range of therapies open to them.

In a project led by specialists at Washington University in St. Louis, Children's and DFCI physicians are about to open a clinical trial of stem cell transplantation for sickle cell patients who do not have an immunologicallymatched sibling donor – the first time unrelated donor transplants have been studied in this group. Caregivers at Children's and Boston Medical Center (BMC) have also developed a protocol in which all pediatric sickle cell patients and families at the two hospitals will be asked if they want to learn about transplantation and determine if they have a potential family donor.

"For at least the past 20 years, it has been known that bone marrow or stem cell transplants using matched sibling donors can cure people with sickle cell disease," says Leslie Lehmann, MD, clinical director of the Pediatric Stem Cell Transplant Program at Dana-Farber and Children's. An inherited condition in which red blood cells assume a crescent shape, the disease impedes the cells' ability to pass through blood vessels and deliver oxygen to organs and tissues. The result can be intense chronic pain, organ damage, and lifethreatening complications such as strokes and bacterial infections. "For a variety of reasons, however, the possibility of curative therapy is unknown to many sickle cell patients," Lehmann notes. "We want to change that."

African Americans, Afro-Caribbeans, and Hispanics are the groups most heavily affected by sickle cell disease in the United States. Unfortunately, they are not well represented in the ranks of those who have been typed as potential donors for unrelated transplants. In Massachusetts, the cost of initial typing, which can amount to $100 per person, is covered by insurance.

The protocol organized by BMC and Children's will ensure that all sickle cell patients at participating hospitals know about transplantation as a treatment option. "We want to be sure young people and their families are aware of both the benefits and potential risks of the treatment," says Matthew Heeney, MD, of Children's and Dana-Farber.

How it works

The transplantation procedure, also used for patients with leukemia and other blood disorders, involves high-dose chemotherapy to destroy diseased bloodmaking tissue in patients' bone marrow, followed by an infusion of healthy stem cells from a compatible donor. The new stem cells replenish the body's supply of red and white blood cells.

Even when patients and their families are informed about the procedure and a matched sibling is available, decisions regarding transplantation are complicated. On the positive side is the promise of a cure. On the negative is the 10 percent chance that a recipient will die from the transplant itself or reject the healthy cells. Also to be considered is the high likelihood that a successful transplantation will render patients infertile and the small possibility that the implanted cells mount an immunological attack on the body, causing graft-versus-host disease, another potentially deadly disorder.

Given this difficult choice, many families choose the middle-ground option of treatment with the drug hydroxyurea, which can be very effective, especially in children, but requires lifelong therapy and may lose some benefit over time.

Although transplants between non-siblings – only a few of which have been performed in the U.S. for this disease – are likely to have lower success rates than conventional transplants, it's important for patients and families to know they're available, particularly when the patient doesn't have a matched brother or sister, Lehmann says. "The choice of therapy is ultimately up to patients and their families. We want to make sure it's a fully informed choice."

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