Medical oncologist Parastoo Dahi (left) specializes in treating patients with stem cell transplants.
What would you do if you found out that your bone marrow was a match for someone who needed it — even a complete stranger?
Bone marrow and stem cell transplants are a lifesaving treatment for many people with blood cancers like leukemia and lymphoma, as well as some other blood diseases.
During a transplant, patients are given high doses of chemotherapy and sometimes radiation to wipe out their cancer. These powerful treatments also destroy the blood-making cells, however. So the next step is for healthy blood stem cells to be infused into the body, enabling the patients to grow new blood cells and recover from the treatment.
Although some patients can use their own stem cells to rebuild the blood, many patients — especially those with leukemia whose blood stem cells may themselves be cancerous — need a donor to provide the cells that will enable them to recover.
One way that donors are found is through the National Marrow Donor Program, a group that maintains a registry to match unrelated volunteer donors with patients in need. Many people are reluctant to join this registry because they don’t understand what’s involved or how important their donation may be. We spoke to Parastoo Dahi, a hematologist and medical oncologist at Memorial Sloan Kettering who specializes in stem cell transplantation, about some of the myths surrounding bone marrow and stem cell donation.
Myth 1: Stem cell donations always come from the bone marrow.
“We still commonly use the term ‘bone marrow transplant,’ but more often than not, what we really mean is a transplant using stem cells that are removed from the bloodstream rather than the marrow,” Dr. Dahi says.
The doctor performing the transplant will decide which procedure will be used to extract the stem cells based on what he or she thinks will be best for the recipient. But the majority of donations are taken from the blood, not the bone marrow.
Myth 2: Making a stem cell donation is difficult and painful.
With stem cell donation from the blood, there is very little pain involved. It is very similar to donating blood platelets. The main difference is that for a few days before the donation, donors need to take an injection called filgrastim (Neupogen®), which stimulates the bone marrow to produce extra blood-forming stem cells. They may experience some bone pain or a low-grade fever while taking filgrastim, but the side effects usually are not severe and go away after the donation process is complete.
Bone marrow donation, the less common form of donation, is a surgical procedure done in an operating room. Donors are given general anesthesia so they don’t feel any pain as the bone marrow is removed, or aspirated, from both sides of their pelvis.
“The procedure takes an hour or two, and usually donors can go home within a few hours of waking up,” Dr. Dahi says. “They may have some pelvic and hip pain, as well as some bruising, for a few days, but most donors can immediately go back to their regular activities. The achiness can generally be controlled with over-the-counter pain medications.”
Myth 3: Stem cell donation is inconvenient.
Leading up to the time of the stem cell donation, most people are able to give themselves injections of filgrastim at home, so they don’t need to go to the doctor every day.
On the day of the donation, the donor is hooked up to what is called an apheresis machine. The blood is collected from one arm, sent through a machine that removes the stem cells, and returned to the other arm. Donors can read or watch movies during the donation process.
Dr. Dahi says the process takes three to four hours, and the donor may need to return a second day, depending on how many cells are retrieved.
In the cases of both bone marrow and blood stem cell donation, the donor cells can be retrieved at a local hospital or blood donor room and shipped to where they are needed. The donor and recipient may live in different states, or even in different countries.
Myth 4: Most patients can find a stem cell donor in their own family, so there’s no reason to join the registry.
The process by which the donor and recipient are matched is called HLA (human leukocyte antigen) typing. It’s not related to blood type but instead has to do with the immune proteins that we all inherit at birth from both of our parents. “The immune system uses these proteins to understand which cells belong to your body and which do not,” Dr. Dahi explains. “An optimal match means that eight out of eight markers are the same.”
According to Dr. Dahi, about one-quarter of patients have a sibling who is a perfect match. This means that about 75% of cancer patients must rely on potential donors from the registry.
Even if a sibling is perfectly matched, there may be medical reasons why they are unable to donate. Medical restrictions include infections such as HIV and hepatitis, autoimmune diseases such as lupus, bleeding problems, and a history of cancer. “It’s important to make sure that the process is safe for both the donor and the patient,” she says.
Myth 5: There are plenty of people already in the stem cell donor registry, so my contribution isn’t needed.
Not everyone who needs a donor is able to find one. “For members of minority groups, there can be major problems finding donors because they tend to be underrepresented in the registry,” Dr. Dahi says. “Different ethnic groups have different HLA types, so a patient’s best chance of finding a donor is someone within their own ethnic group.” It may be even harder for people of mixed ethnic backgrounds to find donors, because their HLA makeup can be more complex.
For patients who are unable to find matched donors, there are other options, including a donation from a family member who is a half-match (called a haploidentical transplant) or using stem cells from donated umbilical cord blood, which don’t require a full match. “We don’t want patients to delay their treatment if they don’t have a perfect match,” she adds, “but it’s still the standard to go with a donor who is a perfect match whenever possible.”
Myth 6: Getting into the stem cell donor registry is a hassle.
Joining the registry is easy. You can go to www.bethematch.org to order a collection kit that will be sent to your house or to find a local drive in your area. Once you get the kit, all it requires is wiping a cotton swab on the inside of your cheek, sealing it in a provided container, and mailing it back.
Because the most successful donors are between the ages of 18 and 44, the National Marrow Donor Program asks that people between the ages of 45 and 60 make a $100 contribution to cover the costs of testing their swab.
