Bone Marrow Transplantation and 

Peripheral Blood Stem Cell Transplantation: Questions and Answers 

Key Points 

• Hematopoietic or blood-forming stem cells are immature cells that can mature 

into blood cells. These stem cells are found in the bone marrow, bloodstream, or 

umbilical cord blood (see Question 1). 

• Bone marrow transplantation (BMT) and peripheral blood stem cell 

transplantation (PBSCT) are procedures that restore stem cells that were destroyed 

by high doses of chemotherapy and/or radiation therapy (see Questions 2 and 3). 

• In general, patients are less likely to develop a complication known as graftversus-host disease (GVHD) if the stem cells of the donor and patient are closely 

matched (see Question 5). 

• After being treated with high-dose anticancer drugs and/or radiation, the patient 

receives the harvested stem cells, which travel to the bone marrow and begin to 

produce new blood cells (see Questions 11 to 13). 

• A “mini-transplant” uses lower, less toxic doses of chemotherapy and/or radiation 

to prepare the patient for transplant (see Question 15). 

• A “tandem transplant” involves two sequential courses of high-dose 

chemotherapy and stem cell transplant (see Question 16). 

• The National Marrow Donor Program® (NMDP) maintains an international 

registry of volunteer stem cell donors (see Question 19). 

1. What are bone marrow and hematopoietic stem cells? 

Bone marrow is the soft, sponge-like material found inside bones. It contains immature 

cells known as hematopoietic or blood-forming stem cells. (Hematopoietic stem cells are 

different from embryonic stem cells. Embryonic stem cells can develop into every type 

of cell in the body.) Hematopoietic stem cells divide to form more blood-forming stem 

cells, or they mature into one of three types of blood cells: white blood cells, which fight 

infection; red blood cells, which carry oxygen; and platelets, which help the blood to clot. 

Most hematopoietic stem cells are found in the bone marrow, but some cells, called 

peripheral blood stem cells (PBSCs), are found in the bloodstream. Blood in the 

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umbilical cord also contains hematopoietic stem cells. Cells from any of these sources 

can be used in transplants.

2. What are bone marrow transplantation and peripheral blood stem cell 

transplantation? 

Bone marrow transplantation (BMT) and peripheral blood stem cell transplantation 

(PBSCT) are procedures that restore stem cells that have been destroyed by high doses of 

chemotherapy and/or radiation therapy. There are three types of transplants: 

• In autologous transplants, patients receive their own stem cells. 

• In syngeneic transplants, patients receive stem cells from their identical twin. 

• In allogeneic transplants, patients receive stem cells from their brother, sister, or 

parent. A person who is not related to the patient (an unrelated donor) also may be 

used. 

3. Why are BMT and PBSCT used in cancer treatment?

One reason BMT and PBSCT are used in cancer treatment is to make it possible for 

patients to receive very high doses of chemotherapy and/or radiation therapy. To 

understand more about why BMT and PBSCT are used, it is helpful to understand how 

chemotherapy and radiation therapy work. 

Chemotherapy and radiation therapy generally affect cells that divide rapidly. They are 

used to treat cancer because cancer cells divide more often than most healthy cells. 

However, because bone marrow cells also divide frequently, high-dose treatments can 

severely damage or destroy the patient’s bone marrow. Without healthy bone marrow, 

the patient is no longer able to make the blood cells needed to carry oxygen, fight 

infection, and prevent bleeding. BMT and PBSCT replace stem cells that were destroyed 

by treatment. The healthy, transplanted stem cells can restore the bone marrow’s ability 

to produce the blood cells the patient needs. 

In some types of leukemia, the graft-versus-tumor (GVT) effect that occurs after 

allogeneic BMT and PBSCT is crucial to the effectiveness of the treatment. GVT occurs 

when white blood cells from the donor (the graft) identify the cancer cells that remain in 

the patient’s body after the chemotherapy and/or radiation therapy (the tumor) as foreign 

and attack them. (A potential complication of allogeneic transplants called 

graft-versus-host disease is discussed in Questions 5 and 14.) 
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4. What types of cancer are treated with BMT and PBSCT?

BMT and PBSCT are most commonly used in the treatment of leukemia and lymphoma. 

They are most effective when the leukemia or lymphoma is in remission (the signs and 

symptoms of cancer have disappeared). BMT and PBSCT are also used to treat other 

cancers such as neuroblastoma (cancer that arises in immature nerve cells and affects 

mostly infants and children) and multiple myeloma. Researchers are evaluating BMT 

and PBSCT in clinical trials (research studies) for the treatment of various types of 

cancer. 

5. How are the donor’s stem cells matched to the patient’s stem cells in allogeneic or 

syngeneic transplantation? 

To minimize potential side effects, doctors most often use transplanted stem cells that 

match the patient’s own stem cells as closely as possible. People have different sets of 

proteins, called human leukocyte-associated (HLA) antigens, on the surface of their cells. 

The set of proteins, called the HLA type, is identified by a special blood test. 

In most cases, the success of allogeneic transplantation depends in part on how well the 

HLA antigens of the donor’s stem cells match those of the recipient’s stem cells. The 

higher the number of matching HLA antigens, the greater the chance that the patient’s 

body will accept the donor’s stem cells. In general, patients are less likely to develop a 

complication known as graft-versus-host disease (GVHD) if the stem cells of the donor 

and patient are closely matched. GVHD is further described in Question 14. 

Close relatives, especially brothers and sisters, are more likely than unrelated people to 

be HLA-matched. However, only 25 to 35 percent of patients have an HLA-matched 

sibling. The chances of obtaining HLA-matched stem cells from an unrelated donor are 

slightly better, approximately 50 percent. Among unrelated donors, HLA-matching is 

greatly improved when the donor and recipient have the same ethnic and racial 

background. Although the number of donors is increasing overall, individuals from 

certain ethnic and racial groups still have a lower chance of finding a matching donor. 

Large volunteer donor registries can assist in finding an appropriate unrelated donor (see 

Question 18). 

Because identical twins have the same genes, they have the same set of HLA antigens. 

As a result, the patient’s body will accept a transplant from an identical twin. However, 

identical twins represent a small number of all births, so syngeneic transplantation is rare. 

6. How is bone marrow obtained for transplantation?

The stem cells used in BMT come from the liquid center of the bone, called the marrow. 

In general, the procedure for obtaining bone marrow, which is called “harvesting,” is 

similar for all three types of BMTs (autologous, syngeneic, and allogeneic). The donor is 

given either general anesthesia, which puts the person to sleep during the procedure, or 

regional anesthesia, which causes loss of feeling below the waist. Needles are inserted 
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through the skin over the pelvic (hip) bone or, in rare cases, the sternum (breastbone), and 

into the bone marrow to draw the marrow out of the bone. Harvesting the marrow takes 

about an hour. 

The harvested bone marrow is then processed to remove blood and bone fragments. 

Harvested bone marrow can be combined with a preservative and frozen to keep the stem 

cells alive until they are needed. This technique is known as cryopreservation. Stem 

cells can be cryopreserved for many years. 

7. How are PBSCs obtained for transplantation? 

The stem cells used in PBSCT come from the bloodstream. A process called apheresis or 

leukapheresis is used to obtain PBSCs for transplantation. For 4 or 5 days before 

apheresis, the donor may be given a medication to increase the number of stem cells 

released into the bloodstream. In apheresis, blood is removed through a large vein in the 

arm or a central venous catheter (a flexible tube that is placed in a large vein in the neck, 

chest, or groin area). The blood goes through a machine that removes the stem cells. The 

blood is then returned to the donor and the collected cells are stored. Apheresis typically 

takes 4 to 6 hours. The stem cells are then frozen until they are given to the recipient. 

8. How are umbilical cord stem cells obtained for transplantation? 

Stem cells also may be retrieved from umbilical cord blood. For this to occur, the mother 

must contact a cord blood bank before the baby’s birth. The cord blood bank may 

request that she complete a questionnaire and give a small blood sample. 

Cord blood banks may be public or commercial. Public cord blood banks accept 

donations of cord blood and may provide the donated stem cells to another matched 

individual in their network. In contrast, commercial cord blood banks will store the cord 

blood for the family, in case it is needed later for the child or another family member. 

After the baby is born and the umbilical cord has been cut, blood is retrieved from the 

umbilical cord and placenta. This process poses minimal health risk to the mother or the 

child. If the mother agrees, the umbilical cord blood is processed and frozen for storage 

by the cord blood bank. Only a small amount of blood can be retrieved from the 

umbilical cord and placenta, so the collected stem cells are typically used for children or 

small adults. 

9. Are any risks associated with donating bone marrow?

Because only a small amount of bone marrow is removed, donating usually does not pose 

any significant problems for the donor. The most serious risk associated with donating 

bone marrow involves the use of anesthesia during the procedure. 

The area where the bone marrow was taken out may feel stiff or sore for a few days, and 

the donor may feel tired. Within a few weeks, the donor’s body replaces the donated 
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marrow; however, the time required for a donor to recover varies. Some people are back 

to their usual routine within 2 or 3 days, while others may take up to 3 to 4 weeks to fully 

recover their strength. 

10. Are any risks associated with donating PBSCs?

Apheresis usually causes minimal discomfort. During apheresis, the person may feel 

lightheadedness, chills, numbness around the lips, and cramping in the hands. Unlike 

bone marrow donation, PBSC donation does not require anesthesia. The medication that 

is given to stimulate the release of stem cells from the marrow into the bloodstream may 

cause bone and muscle aches, headaches, fatigue, nausea, vomiting, and/or difficulty 

sleeping. These side effects generally stop within 2 to 3 days of the last dose of the 

medication. 

11. How does the patient receive the stem cells during the transplant?

After being treated with high-dose anticancer drugs and/or radiation, the patient receives 

the stem cells through an intravenous (IV) line just like a blood transfusion. This part of 

the transplant takes 1 to 5 hours. 

12. Are any special measures taken when the cancer patient is also the donor 

(autologous transplant)? 

The stem cells used for autologous transplantation must be relatively free of cancer cells. 

The harvested cells can sometimes be treated before transplantation in a process known 

as “purging” to get rid of cancer cells. This process can remove some cancer cells from 

the harvested cells and minimize the chance that cancer will come back. Because 

purging may damage some healthy stem cells, more cells are obtained from the patient 

before the transplant so that enough healthy stem cells will remain after purging. 

13. What happens after the stem cells have been transplanted to the patient? 

After entering the bloodstream, the stem cells travel to the bone marrow, where they 

begin to produce new white blood cells, red blood cells, and platelets in a process known 

as “engraftment.” Engraftment usually occurs within about 2 to 4 weeks after 

transplantation. Doctors monitor it by checking blood counts on a frequent basis. 

Complete recovery of immune function takes much longer, however—up to several 

months for autologous transplant recipients and 1 to 2 years for patients receiving 

allogeneic or syngeneic transplants. Doctors evaluate the results of various blood tests to 

confirm that new blood cells are being produced and that the cancer has not returned. 

Bone marrow aspiration (the removal of a small sample of bone marrow through a needle 

for examination under a microscope) can also help doctors determine how well the new 

marrow is working. 
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14. What are the possible side effects of BMT and PBSCT? 

The major risk of both treatments is an increased susceptibility to infection and bleeding 

as a result of the high-dose cancer treatment. Doctors may give the patient antibiotics to 

prevent or treat infection. They may also give the patient transfusions of platelets to 

prevent bleeding and red blood cells to treat anemia. Patients who undergo BMT and 

PBSCT may experience short-term side effects such as nausea, vomiting, fatigue, loss of 

appetite, mouth sores, hair loss, and skin reactions. 

Potential long-term risks include complications of the pretransplant chemotherapy and 

radiation therapy, such as infertility (the inability to produce children); cataracts 

(clouding of the lens of the eye, which causes loss of vision); secondary (new) cancers; 

and damage to the liver, kidneys, lungs, and/or heart. 

With allogeneic transplants, a complication known as graft-versus-host disease (GVHD) 

sometimes develops. GVHD occurs when white blood cells from the donor (the graft) 

identify cells in the patient’s body (the host) as foreign and attack them. The most 

commonly damaged organs are the skin, liver, and intestines. This complication can 

develop within a few weeks of the transplant (acute GVHD) or much later (chronic 

GVHD). To prevent this complication, the patient may receive medications that suppress 

the immune system. Additionally, the donated stem cells can be treated to remove the 

white blood cells that cause GVHD in a process called “T-cell depletion.” If GVHD 

develops, it can be very serious and is treated with steroids or other immunosuppressive 

agents. GVHD can be difficult to treat, but some studies suggest that patients with 

leukemia who develop GVHD are less likely to have the cancer come back. Clinical 

trials are being conducted to find ways to prevent and treat GVHD. 

The likelihood and severity of complications are specific to the patient’s treatment and 

should be discussed with the patient’s doctor. 

15. What is a “mini-transplant”?

A “mini-transplant” (also called a non-myeloablative or reduced-intensity transplant) is a 

type of allogeneic transplant. This approach is being studied in clinical trials for the 

treatment of several types of cancer, including leukemia, lymphoma, multiple myeloma, 

and other cancers of the blood. 

A mini-transplant uses lower, less toxic doses of chemotherapy and/or radiation to 

prepare the patient for an allogeneic transplant. The use of lower doses of anticancer 

drugs and radiation eliminates some, but not all, of the patient’s bone marrow. It also 

reduces the number of cancer cells and suppresses the patient’s immune system to 

prevent rejection of the transplant. 

Unlike traditional BMT or PBSCT, cells from both the donor and the patient may exist in 

the patient’s body for some time after a mini-transplant. Once the cells from the donor 

begin to engraft, they may cause the graft-versus-tumor (GVT) effect and work to destroy 
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the cancer cells that were not eliminated by the anticancer drugs and/or radiation. To 

boost the GVT effect, the patient may be given an injection of their donor’s white blood 

cells. This procedure is called a “donor lymphocyte infusion.” 

16. What is a “tandem transplant”? 

A “tandem transplant” is a type of autologous transplant. This method is being studied in 

clinical trials for the treatment of several types of cancer, including multiple myeloma 

and germ cell cancer. During a tandem transplant, a patient receives two sequential 

courses of high-dose chemotherapy with stem cell transplant. Typically, the two courses 

are given several weeks to several months apart. Researchers hope that this method can 

prevent the cancer from recurring (coming back) at a later time. 

17. How do patients cover the cost of BMT or PBSCT?

Advances in treatment methods, including the use of PBSCT, have reduced the amount of 

time many patients must spend in the hospital by speeding recovery. This shorter 

recovery time has brought about a reduction in cost. However, because BMT and 

PBSCT are complicated technical procedures, they are very expensive. Many health 

insurance companies cover some of the costs of transplantation for certain types of 

cancer. Insurers may also cover a portion of the costs if special care is required when the 

patient returns home. 

There are options for relieving the financial burden associated with BMT and PBSCT. A 

hospital social worker is a valuable resource in planning for these financial needs. 

Federal Government programs and local service organizations may also be able to help. 

The National Cancer Institute’s (NCI) Cancer Information Service (CIS) can provide 

patients and their families with additional information about sources of financial 

assistance (see below). 

18. What are the costs of donating bone marrow, PBSCs, or umbilical cord blood?

Persons willing to donate bone marrow or PBSCs must have a sample of blood drawn to 

determine their HLA type. This blood test usually costs $65 to $96. The donor may be 

asked to pay for this blood test, or the donor center may cover part of the cost. 

Community groups and other organizations may also provide financial assistance. Once 

a donor is identified as a match for a patient, all of the costs pertaining to the retrieval of 

bone marrow or PBSCs is covered by the patient or the patient’s medical insurance. 

A woman can donate her baby’s umbilical cord blood to public cord blood banks at no 

charge. However, commercial blood banks do charge varying fees to store umbilical 

cord blood for the private use of the patient or his or her family. 
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19. Where can people get more information about potential donors and transplant 

centers? 

The National Marrow Donor Program® (NMDP), a federally funded nonprofit 

organization, was created to improve the effectiveness of the search for donors. The 

NMDP maintains an international registry of volunteers willing to be donors for all 

sources of blood stem cells used in transplantation: bone marrow, peripheral blood, and 

umbilical cord blood. 

The NMDP Web site contains a list of participating transplant centers at 

http://www.marrow.org/ABOUT/NMDP_Network/Transplant_Centers/index.html on the 

Internet. The list includes descriptions of the centers as well as their transplant 

experience, survival statistics, research interests, pretransplant costs, and contact 

information. 

Organization: National Marrow Donor Program 

Address: Suite 100 

 3001 Broadway Street, NE. 

 Minneapolis, MN 55413–1753 

Telephone: 612–627–5800 

 1–800–627–7692 (1–800–MARROW–2) 

 1–888–999–6743 (Office of Patient Advocacy) 

E-mail: patientinfo@nmdp.org

Internet Web site: http://www.marrow.org 

20. Where can people get more information about clinical trials of BMT and PBSCT?

Clinical trials that include BMT and PBSCT are a treatment option for some patients. 

Information about ongoing clinical trials is available from NCI’s Cancer Information 

Service (see below), or from the NCI’s Web site at http://www.cancer.gov/clinicaltrials 

on the Internet. 

# # # 

Related NCI materials and Web pages: 

• National Cancer Institute Fact Sheet 2.11, Clinical Trials: Questions and Answers

(http://www.cancer.gov/cancertopics/factsheet/Information/clinical-trials) 

• Chemotherapy and You: Support for People With Cancer

(http://www.cancer.gov/cancertopics/chemotherapy-and-you)

• National Cancer Institute National Organizations That Offer Services to People With 

Cancer and Their Families Database 

(http://www.cancer.gov/cancertopics/factsheet/Rehabilitation/organizations)
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• Radiation Therapy and You: Support for People With Cancer

(http://www.cancer.gov/cancertopics/radiation-therapy-and-you)

• Taking Part in Cancer Treatment Research Studies

(http://www.cancer.gov/clinicaltrials/Taking-Part-in-Cancer-Treatment-ResearchStudies)

• What You Need To Know AboutTM Hodgkin Lymphoma 

(http://www.cancer.gov/cancertopics/wyntk/hodgkin)

• What You Need To Know AboutTM Leukemia

(http://www.cancer.gov/cancertopics/wyntk/leukemia)

• What You Need To Know AboutTM Multiple Myeloma

(http://www.cancer.gov/cancertopics/wyntk/myeloma)

• What You Need To Know AboutTM Non-Hodgkin Lymphoma

(http://www.cancer.gov/cancertopics/wyntk/non-hodgkin-lymphoma)

For more help, contact: 

NCI’s Cancer Information Service 

Telephone (toll-free): 1–800–4–CANCER (1–800–422–6237) 

TTY (toll-free): 1–800–332–8615

LiveHelp® online chat: https://cissecure.nci.nih.gov/livehelp/welcome.asp

This fact sheet was reviewed on 8/31/04