Download Stem Cell Transplant Fact Sheet

Leukemia is a malignant cancer affecting the bone marrow and blood. All leukemias
develop from a cell in the bone marrow, which undergoes a genetic change causing it to
grow and multiply out of control. These leukemia cells eventually crowd out normal
cells in the marrow.
According to the Canadian Cancer Society, an estimated 4,200 Canadians were
diagnosed with leukemia in 2007. Within five years, nearly 2,000 of those people will
die of their illness.
There are several types of leukemia. These can be divided into categories: myelogenous
or lymphocytic (based on the type of blood cell affected); acute or chronic (based on the
speed of progression of the disease). Acute leukemias develop rapidly and tend to grow
aggressively, thus treatment is generally much more urgent than for chronic leukemias.
The most common type of acute leukemia affecting adults is acute myelogenous
leukemia (AML), of which there are several subtypes. The most common adult
leukemia overall is chronic lymphocytic leukemia (CLL). Other common types include
acute lymphocytic leukemia (ALL) and chronic myelogenous leukemia (CML).
According to the Canadian Cancer Society, there were 957 new cases of AML in Canada
in 2004 (versus 307 cases of ALL, 397 cases of CML, and 1786 cases of CLL).
The prognosis for patients with AML depends on many factors, including the age of the
patient, the subtype of AML, the specific genetic changes in the cancer cells, and the
response of the disease to initial treatment.
Treatment of AML is individualized for each patient, and can involve one or more of:
(a) chemotherapy, (b) radiation therapy, and (c) stem cell transplantation.
Stem cells in the bone marrow are cells that can generate all types of mature blood cells:
red cells (which carry oxygen to the body), white cells (which help to fight infections),
and platelets (which are involved in blood clotting).
In many patients with AML, especially if initial chemotherapy is not effective, stem cell
transplant (bone marrow transplant) may be the only way to cure the disease.
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In order to perform a bone marrow transplant, a suitable donor must be found. (Note
that gender is not important: men can donate stem cells to women and vice versa)
All cells in the body carry special markers on their surface that tell the body that they
belong to itself, and are not "foreign" and therefore not rejected. Those found on bone
marrow stem cells are called "human leukocyte antigens" (HLA).
We all have 6 major pairs of HLA markers on our cells. Each person inherits one of each
pair of antigens from each parent. There are dozens of variations of each of these
markers, and therefore millions of potential combinations of all six. This is why it can be
difficult to find a perfect match for a patient in need of transplant.
Because we inherit half of our HLA markers from our mother and half from our father,
each brother and sister who has the same parents has a 25% chance of matching. It is
unlikely that extended family members will match. However, parents and/or children
may also be tested to confirm HLA typing and to make sure no possible donors are
overlooked.
A close HLA match improves the chances for a successful transplant. Close matching:
(a) promotes engraftment (when the donated cells start to grow and make new blood
cells); and (b) reduces the risk of a post-transplant complication called graft-versus-host
disease (GVHD). GVHD occurs when the immune cells from the donated marrow (the
graft) attack the recipient's cells (the host).
About 70% of patients who need a transplant do not have a suitable donor in their
family. If there is no related donor, doctors will search national and international bone
marrow donor registries for potential matched unrelated donors.
Bone Marrow Donors Worldwide (BMDW) is a collective database of 59 stem cell donor
registries from 43 countries (including Canada), and 40 cord blood banks from 25
countries; 12,441,390 potential donors and cord blood units were available as of August
26, 2008. A very small registry in India (Asian Indian Donor Marrow Registry) also
participates in this program, but has only about one thousand registrants so far.
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The process of registering to becoming a potential donor in Canada is free, simple, and
completely non-invasive.
In Canada, Canadian Blood Services (CBS) operates "OneMatch" (www.onematch.ca),
the national database of stem cell donors. Much of the following information about
registration and donation is taken from their website.
Anyone between the ages of 17 and 50 who is in good general health can join. To
register, visit www.onematch.ca and fill out the online registration form. If joining
online is not possible, call 1-888-2-DONATE (1-888-236-6283) to have a registration
package mailed to you.
After receiving general registration information, OneMatch will contact you to ask
further questions and to discuss the donation process. You will then be mailed a kit
containing four swabs; simply use them to swab four areas of your mouth (between
your cheeks and gums), and mail the swabs back to CBS in the pre-paid envelope.
Detailed instructions are included with the swab package.
OneMatch will use the skin cells on the swabs to genetically test for your HLA types.
These test results will be entered into the national database, and your information will
be included when physicians search for possible donors for patients in need.
OneMatch conducts database searches to find a donor whose HLA markers match that
of the patient in need of a stem cell transplant. In the event that you come up as a likely
match, OneMatch will contact you. If you agree to proceed (you are free to decline at
any point), further blood tests will be scheduled to determine the full extent of your
compatibility and to test for transmissible diseases (such as HIV, hepatitis B/C, etc).
Your health will be thoroughly assessed to make certain that you can safely proceed
and to ensure that your health background does not pose a risk to the patient. If you are
selected to donate, you will be guided through this process by a case manager. The case
manager will conduct an assessment over the phone, then a transplant physician will
perform a thorough physical assessment at the collection centre (the hospital where you
will donate stem cells) closest to you. You will also be tested to confirm that you have
no infectious diseases.
Once it is determined that you are medically eligible and you agree to proceed, the
patient will be notified and the elimination of his or her diseased bone marrow will
begin.
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It is important to understand that donating bone marrow for transplant is NOT like
donating an organ (such as a kidney or liver). It is much more similar to donating
blood: it involves very little pain; it is a short, minimally-invasive procedure; there is
complete regeneration of the bone marrow; and there are no significant complications.
Bone marrow stem cell donation is a surgical procedure performed under anaesthesia in
an operating room. The collection physician will use special, hollow needles to
withdraw liquid marrow from the back of your pelvic (hip) bones, not from the spine (see
diagram). Normally, about a litre of fluid is taken altogether.
The procedure usually lasts from 45-90 minutes, and donors are normally discharged
from the hospital the same day.
You can expect to feel some soreness in the back of your hips for a few days or longer.
Most donors are back to their normal routine in a few days. Your marrow is completely
replaced within four to six weeks.
Everyone's pain tolerance is different, but most donors report that any discomfort they
feel is easily managed with pain medication that is ordered for them if required. Many
donors report very little discomfort.
Bone marrow is harvested on the same day as transplantation, with the intent to infuse
the recipient within 24 hours of the harvest. The harvested marrow is filtered and given
to the recipient intravenously.
Generally, donors are kept anonymous from the recipient until one year after
transplant. At this time, identifying information can be exchanged if mutually desired.
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While the urgent stimulus for this donor recruitment drive comes from the need of one
member of our community, registering for the stem cell donor database also has the
potential to save the lives of thousands of people around the world.
It is especially imperative for members of the South-Asian community to register, as we
are extremely under-represented within the database. In other words, although SouthAsians represent a significant proportion of the general population, members of our
community in need of a bone marrow transplant are much less likely to find a donor.
According to the U.S. National Cancer Institute, among different ethnic groups, the
probability of finding a good (6/6) match is, from the highest to lowest, Japanese (99%),
North American Caucasian (93%), African American and Asian (50%).
Please note that even if you are not eligible to donate stem cells due to your age or
health, you can still help by making a financial contribution to organizations such as
Canadian Blood Services and the Canadian Cancer Society.
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Some useful websites for more information:
Toronto Star article about Dr. A. Guha: http://www.thestar.com/article/486109
Vancouver Sun article about Dr. A. Guha:
http://www.canada.com/vancouversun/news/westcoastnews/story.html?id=2e06ae41
-99a4-436c-88ac-b5b2141b152d
Dr. A. Guha’s lab website: http://www.sickkids.on.ca/Guha/default.asp
Canadian bone marrow donation: http://www.onematch.ca/
U.S. bone marrow donation: http://www.marrow.org/
Indian bone marrow donation: http://www.matchpia.org/
Leukemia information: http://www.leukemia-lymphoma.org/all_page?item_id=7026
Canadian Cancer Society: http://www.cancer.ca/
Information about stem cells and cancer (U.S. National Cancer Institute):
http://www.cancer.gov/cancertopics/understandingcancer/stemcells
International stem cell donor database: http://www.bmdw.org/