Resources

Resource Guide for Bone Marrow/Stem Cell Transplant
Friends Helping Friends

Understanding the Process

Bone marrow is the spongy tissue found in the cavities of the body’s bones where all of the blood cells are produced. Every type of blood cell in the marrow begins its life as a stem cell. A stem cell is often defined as a “parent cell” which divides and forms the different cells that make up the blood and immune system. Stem cells are found in the bone marrow, in cord blood, and, in smaller numbers, in the circulating (peripheral) blood. Stem cells produce:

• White cells (leukocytes) that fight infection
• Red cells (erythrocytes) that carry oxygen
• Platelets that are clotting agents

The goal of a stem cell transplant is to cure many different types of cancer and disease. The type of transplant you have will depend on who donates the stem cells.

• Autologous transplant—The patient donates his/her own stem cells prior to treatment for reinfusion later.
• Allogeneic related transplant—The person donating the stem cells is a genetically-matched family member (usually a brother or sister).
• Allogeneic unrelated transplant—The person donating the stem cells is not related to the patient.
• Syngeneic transplant—The person donating the stem cells is an identical twin.

Stem cells can be collected from the following sources:

• bone marrow
• peripheral blood
• cord blood

Many elements of your transplant are beyond your personal control. It may be a good time to shift your focus to those factors that can be controlled or influenced by you. You should begin to investigate what resources you will have available to you before, during, and after transplant. It is important that you educate yourself about the transplant procedure.

Autologous Transplants
When patients give their own stem cells back to themselves, the procedure is called an autologous stem cell transplant. How can a sick person be his/her own donor and then get healthy again? It helps to think of this kind of transplant as a rescue. You may even hear your health care team refer to your transplant as a rescue. The autologous transplant isn’t necessarily performed because there’s something wrong with the bone marrow or stem cell production. It’s performed because the dosage of chemotherapy and radiation needed to kill the disease is so high that it will destroy the patient’s existing bone marrow. Without the stem cells in the marrow, there is no blood cell production or immune system, and life is not sustainable. The patient’s own stem cells, collected prior to the chemotherapy/ radiation, are reinfused, like a blood transfusion, and blood cell production and the immune system are re-established. Generally, patients not achieving remission are not suitable candidates to donate stem cells for themselves.

Oddly enough, however, cancers that originate in the bone marrow, such as certain types of leukemia, are sometimes treated with autologous stem cell transplants, particularly if it is not possible to use the stem cells of a donor. Since the marrow is where the cancer originates, it is difficult to obtain totally unaffected stem cells. Even when the patient is in remission, it’s possible for some cancer cells to remain in the body. In order to deal with this, many transplant centers have developed methods of purging or cleansing the stem cell product and ridding it of most of the cancerous cells. The goal is to keep the diseased cells in such a small number that the body’s defense system will be able to destroy them. Purging is done differently from center to center. Some centers, in fact, don’t do it at all. If you have questions about these issues, ask them. Your doctor and other medical professionals should be able to get you the information that you need.

Allogeneic Transplants
Related and unrelated allogeneic, and syngeneic transplants are most commonly used in persons with diseases affecting bone marrow, such as leukemia, aplastic anemia, and some lymphomas. The idea is to replace unhealthy marrow with healthy marrow. Sometimes a disease, such as leukemia, interferes with the stem cell growth, causing cells to stop developing and/or become defective. Eventually these abnormal or immature cells enter the bloodstream causing serious illness. A stem cell transplant provides healthy stem cells to patients whose marrow is diseased. The transplant is actually the transfer of healthy stem cells from a donor to a recipient.

The Donor
Autologous SCT patients will receive their own bone marrow or blood stem cells that were retrieved before transplant. In this case, the patient is his/her own donor.

Allogeneic SCT patients must have a donor identified for them in order to receive new stem cells. The choice of donor and source of stem cells will be determined by your physician. You should understand the rationale for choosing a particular donor and source of stem cells. Often a donor is a brother, sister, or another family member. Each sibling offers a 25% chance of being a match. Having an identical twin sets you up for a perfectly matched syngeneic transplant.

When there’s no related donor match for you, a search is initiated to locate a “matched unrelated donor” (MUD). How are unrelated matches found? There are a number of donor and cord blood registries worldwide. The National Marrow Donor Program is one of the largest computerized registries and keeps an extensive database of potential donors and cord blood units. The chance of finding an unrelated donor from the general population depends on the uniqueness of your tissue type. Genetic and ethnic background may also affect the likelihood of finding a donor. With the availability of more accurate laboratory tests, the ability to identify closely matched donors is improving.

Knowing who should and should not be tested as a donor is often a topic of concern. Friends, coworkers and others interested in becoming a stem cell donor may either contact a local donor center or one of the large registries like the National Marrow Donor Program (see Resource Listing). These organizations will be aware of when and where donor drives are occurring. The general criteria for becoming a donor include factors such as general health status, weight, and age. Those who will generally not be able to serve as a stem cell donor include people with a history of severe heart problems, cancer, hepatitis, insulin dependent diabetes, or HIV. Cord blood units undergo a similar screening process. Donors are screened for conditions that would put them at too great a risk to donate as well as for illnesses that could be harmful to the patient.

Your transplant center contacts the registries to begin a preliminary donor search. There is no cost for a preliminary search. Charges for a formal search vary, so check with your insurance company to find out what coverage is offered regarding donor searches. If you have questions about any part of the donor search process, speak to your doctor or transplant coordinator. Don’t be in the dark about the status of your search.

Two factors are important in locating a match. The first is a test known as HLA (human leukocyte antigen) typing. The antigen is a substance, acting like a marker, unique to you, not unlike a set of fingerprints. A simple blood test is all it takes to begin the process of HLA typing. Most HLA typing today is performed using a DNA based method to match patients and donors. DNA testing allows patients and donors to be more closely matched. The goal is to find a match for at least six key antigens. The ability to identify donors is improving and some transplant centers are trying to match even more antigens.

The second factor in finding a matched unrelated donor may be the amount of representation of your ethnic or racial group in the registries. Because these antigen/tissue types are inherited, and some are unique to racial or ethnic backgrounds, the greatest chance of locating a donor may come from the same group. A lack of donors in your ethnic or racial group may make it more difficult to locate a match. Ambitious efforts to increase the number of minority donors on the registries are underway.

You do not have to have the same blood type as your donor to be a suitable match. If blood types are different, the patient will become the donor’s blood type after the transplant. This is because the stem cells from a donor have been “programmed” to produce the donor’s blood type and will continue to do that in their new environment.

A cord blood transplant may be a possibility if you meet specific criteria. The use of cord blood is based on the size of the unit as the number of stem cells required is based on the patient’s weight. Some transplant centers are conducting research to combine multiple cord units for transplant in order to provide the necessary number of stem cells.

It is important to remember that it takes time to carry out a donor search. Your transplant center manages the search and will inform you of the results. If you’ve been told there are potential unrelated donor matches for you, more time is required to identify the best matched donor. A formal search begins to narrow down candidates and generally takes several weeks or months (a cord blood search usually takes less time). If a donor is located, willing, and eligible, then final evaluation begins. If no suitable matches are found, other strategies need to be discussed with your doctor.

Bone Marrow Stem Cell Transplant
Stem cells are collected from the patient’s or donor’s bone marrow. Historically, this has been the “traditional” transplant and requires general anesthesia in an operating room. Stem cells are collected from the hip bone. When stem cells are collected from the bone marrow, a large needle is inserted into the back of the hipbone and marrow is withdrawn. The hip bones in the pelvis are marrow-rich bones. Since this procedure is performed under anesthesia, the donor doesn’t feel anything during the marrow collection but may experience some discomfort in the back area for a few days afterward. About 5–10% of the donor’s marrow is withdrawn, an amount that the body easily replenishes within just a few weeks. This process is known as bone marrow retrieval (sometimes referred to as a “harvest”) and is done in an outpatient surgery center.

Peripheral Blood Stem Cell Transplant
When stem cells are taken from the circulating blood, the procedure is more like a blood donation. The stem cells in the circulating blood are called peripheral blood stem cells (PBSC). Like the stem cells in the bone marrow, they are able to divide and produce red cells, white cells and platelets. The concentration of peripheral blood stem cells in the blood, however, is very low. In order to collect them, medications known as colony stimulating factors or growth factors are given to the donor to stimulate the bone marrow to produce more stem cells, which are then released into the blood stream. The growth factors are administered as injections under the skin daily for a maximum of five days duration. Once they are in the blood, these stem cells are collected in one or more sessions normally taking four to six hours each. Stem cell collections are performed as outpatient procedures. Donors should plan to spend most of the day in the hospital on the day of collection. In this procedure, which is called apheresis, the blood circulates through a machine called a cell separator that removes the peripheral stem cells and returns the rest of the blood to the body. The stem cells are then stored and frozen until the time of the transplant for autologous bone marrow transplants. If the stem cells are collected from a related or unrelated donor, they are given immediately.

Cord Blood Transplant
Since the first cord blood transplant (CBT) in 1988, tremendous strides have been made in this field. Generally, CBT is not offered as a treatment option outside of clinical trials. It is mainly offered to children or young adults who meet the criteria for enrollment in these clinical trials. However, recently conducted research trials have demonstrated suitability of cord blood transplants in a selected group of adult patients. Since the number of stem cells required for transplant are based on body weight, most CBT’s are used with patients weighing less than 90 pounds. To overcome this limitation, some transplant centers are conducting clinical trials in which two different cord blood units are combined. There are far-reaching applications for the use of umbilical cord blood stem cells for transplant. The advantages are many. It can be frozen, stored, and readily available. Cord blood also poses a lower risk of graft-versus-host disease (GVHD) and when GVHD does occur, it seems to be milder.

Umbilical cord blood is a rich source of stem cells. The umbilical cord stem cells, instead of being discarded, may be removed from the placenta and attached umbilical cord after delivery of a baby. This procedure poses no danger to the mother or child’s health. The cord blood unit can then be frozen and stored for future transplant. Arrangements for the collection of the cord blood unit must be made several months prior to the expected date of delivery. Unless there is an existing reason to save a cord blood unit for a family member, the current medical recommendation advises against long-term cord blood storage. However, some hospitals allow parents the opportunity to donate their child’s umbilical cord blood to an unrelated donor registry. Interested parents should speak with their doctor about this option. Improved coordination of the cord blood registries and increased cord blood unit donation will help in identifying suitable cord blood products. CBT may be particularly valuable in meeting the desperate need for stem cell donors in minority groups. Readers are advised to discuss the most recent recommendations for CBT or cord blood donation with their physician to keep up with the latest findings.

Transplant Variations
Like other medical science fields, as more is learned about various diseases, new strategies are considered. Stem cell transplant holds great promise. The number of people who benefit from transplant continues to grow. Some remarkable techniques and newer trends in stem cell transplant include:

Non-myeloablative Transplants
One treatment option is the non-myeloablative transplant, sometimes referred to as a “mini” or reduced intensity transplant. The non-myeloablative transplant utilizes lower doses of chemotherapy and radiation. The donor’s cells and patient’s cells “co-exist” in the body for a while and work together to fight cancer cells. Non-myeloablative transplants often require a matched donor. In some cases a mismatched donor may be used. This procedure is a promising option for older patients or those who might not be able to tolerate full dose treatment. People who do not have cancer, but rather an inherited immune blood disorder or an immunodeficiency, may also benefit from this treatment. Strategies are being evaluated, and researchers are “cautiously optimistic” about the nonmyeloablative transplant option. Because data are not yet complete, it is too early to offer long-term success rates.

Tandem Transplants
These are specifically timed autologous transplants designed to prevent the disease from returning at a later time. Enough stem cells are collected (prior to first transplant) to rescue the patient after two sessions of high dose chemotherapy/radiation.

T-Lymphocyte Depletion
In some cases, the stem cells that are collected undergo a process known as Tlymphocyte depletion. In this process, T-lymphocytes, a type of white blood cell, are removed from the stem cells before they are given to the patient. This is done to reduce the incidence of graft-versus-host disease (GVHD), which is caused by the new immune system attacking healthy cells in the patient because it does not recognize the patient as “self.” Removing the T-lymphocytes makes it less likely that the new immune system will mount an attack against the patient.

However, T-lymphocytes are also beneficial as they help the donated stem cells take hold or engraft, and they play a role in reducing the risk of relapse. Although T-lymphocytes pose a risk to the patient because they attack healthy cells — as in GVHD — they also attack residual cancer cells in a process known as graft versus leukemia effect, thus reducing the risk of relapse.

Donor Lymphocyte Infusion (DLI)
This presents a new strategy for managing relapse after SCT for patients with hematological malignancies such as CML, AML or ALL. The patient does not require chemotherapy or radiation prior to this therapy. DLI is associated with significant risk due to graft-versus-host disease and low white blood cell count that increases the patient’s susceptibility for infection and bleeding.

In the future, DNA technology (gene testing) will lead to a better understanding of what triggers malignancies in the body’s cells, and high doses of chemotherapy may be replaced with new treatment options.

Second Transplants
A second transplant may be recommended if a disease returns following transplant or if the donor’s cells do not engraft. The type of treatment and source of cells will depend on the circumstances. This generally poses increased risk as the patient has already had extremely high doses of chemotherapy/radiation or a prolonged period of being immune compromised. In some cases, following an autologous stem cell transplant, a second transplant using donor cells may prove beneficial for treating relapsed disease.

Your doctor will discuss with you what type of transplant and what source of stem cells is best for you. Many factors determine the type of transplant including the disease being treated, previous treatments, age, general health, donor availability, and method of stem cell collection. It will be up to you and your doctor to decide how the transplant is handled. Whatever method is used for the stem cell collection, the desired outcome is the same—that the retrieved stem cells will flourish in the recipient.

Clinical Trials
Part of making an informed decision about having a stem cell transplant involves learning about clinical trials, which test new approaches, new drugs, and new protocols. These are long-term research studies that evaluate promising treatments for cancer and other diseases treatable by stem cell transplants. Transplant-related side-effects and complications are also being studied. Clinical research studies are conducted in several forms. These include national studies sponsored by the National Institutes of Health, single institution studies, and cooperative studies between institutions.

Clinical research studies validate new treatment in three phases. Phase I research studies establish optimal dosage. In phase II research, safety and effectiveness are carefully defined. Phase III studies compare and contrast a new treatment with standard treatment. In this phase, patients who participate are randomly assigned to receive one treatment or the other.

The potential benefits of participation in a clinical trial include:

• Specialized care and strict adherence to protocols
• Careful monitoring during treatment and close follow-up afterward
• Being among the first to benefit from new treatments
• Treatment expenses may be lessened

The potential drawbacks of participation may include:

• Unknown side effects
• May not be right for you
• Insurance coverage may be inadequate

Ask your doctor or medical center to locate where clinical research studies are being conducted. One source for a listing of independent clinical trials is the Physician’s Data Query (PDQ). It is a computer database focusing on cancer treatment information. To find out about these studies, contact the National Cancer Institute (see Resource Listing).

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