Bone marrow is sponge-like material found in certain bones. It makes important blood cells including red blood cells, white blood cells, and platelets. Damage marrow can slow or stop the production of healthy blood cells. This can lead to a number of health issues. For example, weak red blood cells make it difficult to transport oxygen throughout the body. Low white blood cells weaken the immune system. Low platelets can lead to excess bleeding. Both cancer and cancer treatment can damage the marrow.
Bone marrow transplantation (BMT) replaces damaged bone marrow with healthy bone marrow from a donor. It may need to be done with cancers, such as leukemia, lymphoma, and myeloma. It may also be needed to treat myelodysplastic syndromes.
- How does bone marrow transplantation work?
- What is bone marrow transplantation used for?
- What are the types of bone marrow transplantation?
- What does bone marrow transplantation involve?
- What adverse effects can occur with bone marrow transplantation?
How Does Bone Marrow Transplantation Work?
Stem cells can grow into any type of blood cells. Most are found in the bone marrow. Some called, peripheral blood stem cells (PBSCs), can be found in the blood. If PBSCs are used in the transplant, it is referred to as peripheral blood stem cell transplantation (PBSCT). Umbilical cord blood also contains stem cells. They are used in stem cell transplantation.
Donor stem cells are passed into the blood. They will then find their way to bone marrow and begin to make healthy blood cells.
What Is Bone Marrow Transplantation Used for?
Chemotherapy and radiation therapy target cancer cells but healthy fast growing cells can also be damaged. BMT is used to replace damaged bone marrow with with healthy, noncancerous cells. Damage to stem cells can result from:
- Cancer process
- Chemotherapy
- Radiation therapy
BMT cannot be used as a prevention measure. It also cannot reverse damage if the bone marrow is completely destroyed.
Bone marrow damage can be caused by:
- Chemo- and/or radiation therapy directed at the bone marrow—common in treatment of blood cancers like leukemias or lymphomas
- Systemic therapy that affects all cells in the body, including stem cells.
BMT and PBSCT are most frequently used in the treatment of the following cancers:
- Acute lymphoblastic leukemia (ALL)
- Acute myeloid leukemia (AML)
- Chronic myeloid leukemia (CML)
- Multiple myeloma
- Hodgkin's lymphoma
- Non-Hodgkin's lymphoma
- Neuroblastoma
The roles of BMT and PBSCT are under investigation for the following cancers:
What Are the Types of Bone Marrow Transplantation?
Stem cells from your own blood or bone marrow are collected. They are placed in frozen storage before high-dose chemotherapy for cancer. Once chemotherapy treatment is complete, the stem cells are put back into your body. The stem cells will restore the bone marrow and blood cells.
Stem cells from a donor will be used. The donor's tissue type must closely match yours. There are several types of allogeneic transplants:
- Syngeneic—The donor is your identical twin.
- Related—The donor is related to you, usually a brother or sister.
- Unrelated—The donor is no relation to you.
Only an identical twin has the same exact tissue type as your own. Those with the same biological mother and father have a 25% chance of matching your tissue type. If no one in your family is a match, your doctor can search for a donor in the National Marrow Donor Program's Registry.
The following tables list approximate 3-year disease-free survival rates for autologous and allogeneic transplants. Disease-free survival means that you are living without any evidence that your disease or cancer has come back.
| Disease | 3-year Disease-free Survival |
|---|---|
| AML (1st complete remission)* | 54% |
| AML (2nd complete remission) | 73% |
| ALL (1st complete remission)** | 91% |
| CML (1st chronic phase)** | 93%-96% (depending on donor relation) |
| Hodgkin's lymphoma (1st complete remission) | 83% |
| Non-Hodgkin's lymphoma (1st complete remission) | 72% |
*Complete remission (CR) is a decrease in tumor burden by several orders of magnitude. In addition, bone marrow examinations and peripheral blood counts are normal and there is no detectable leukemia elsewhere in the body. **Data for first 100 days after transplant only.
| Disease | 3-year Disease Free Survival |
|---|---|
| AML (1st complete remission) | 48% |
| AML (after 2nd complete remission) | 48% |
| ALL (1st complete remission) | 58% |
| ALL (2nd complete remission) | 46% |
| CML (1st chronic phase) | 57% |
| CML (Accelerated) | 43% |
| CML (blastic)* | 48% |
| Non-Hodgkin's lymphoma (1st complete remission)** | 88% |
*Data for 1 year after transplant only. **Data for first 100 days after transplant only.
What Does Bone Marrow Transplantation Involve?
The donor is given a medicine to numb the area. Several small cuts are made in the skin over the area where the marrow will be removed. A large needle is inserted through the cuts and into the center of the bone. The marrow is drawn up into the needle. This process takes about 1 to 2 hours.
Blood and bone fragments are taken out of the marrow. Other steps may include:
- Autologous transplant—usable stem cells are separated from any cancer cells that may be in the blood.
- Autologous transplant—the marrow may be immediately transfused back or frozen for many years.
- Allogeneic transplant—the marrow is mixed with the preservative DMSO and frozen until it is needed.
Stem cells from the blood are collected with apheresis or leukopheresis. Medicine may be given to increase the number of stem cells in the blood about 4 to 5 days before the procedure.
A needle is placed in a vein in the neck, chest, or arm. Blood passes through the needle and tubes to a machine. There stem cells are removed from the blood. The blood is then returned to the body and the stem cells are stored. Apheresis takes about 4 to 5 hours. The stem cells are frozen until they are needed.
This is now the more common method of getting stem cells.
Treatment may be needed to prepare the body for stem cells. Radiation therapy and/or high-dose chemo may be used to destroy the original cancer. It can also create space in the bone for the new stem cells to grow.
The stem cells will then be delivered through a tube in the chest or neck.
What Adverse Effects Can Occur With Bone Marrow Transplantation?
The transplant can cause some side effects. Most will happen when the body is being prepared for stem cells. Major complications associated with transplantation include:
- Graft failure or rejection
- Infection
- Pneumonitis
- Veno-occlusive disease
- Graft-versus-host disease
- Disease recurrence
- Short-term side effects
- Death
Graft failure is also known as rejection. It is when the marrow does not recover or fails after a brief recovery. It is pretty rare. Another transplant may be done.
Infection is the most common side effect. About half of all infections occur in the first 4 to 6 weeks. It is often caused by bacteria from your skin or intestines.
An infection may also be caused by a fungus. This is far less common.
Viral infections can occur too. Some viruses like herpes simplex virus (HSV) may already be in the body. A weakened immune system will let it become active again. You may be given antiviral medication to help prevent or treat these infections.
To help prevent infection, your healthcare team will likely do the following:
- Maintain a protective environment
- Help you maintain good hygiene
- Check vital signs often and do exams
This type of pneumonia occurs within the first 100 days of the transplant. It may be caused by a bacteria or virus. Risk factors for developing interstitial pneumonitis include:
- Use of drugs that weaken the immune system
- Lung damage—can be caused by radiation therapy
- Total body irradiation.
- Presence of opportunistic infections—happens because immune system is weak
Veno-occlusive disease (VOD) is blockage of the central veins of the liver. It can slow blood flow in veins and damage the liver.
The white blood cells in the donated marrow see your cells as foreign and attack them. This condition is usually treated with steroids or other medicine.
GVHD is divided into acute and chronic:
- Acute—This occurs within 100 days of transplant. Target organs are the skin, the gastrointestinal tract, and the liver.
- Chronic—This typically occurs more than 100 days after transplant. Almost every organ can be affected by chronic GVHD.
Cancer recurrence (relapse) is the most significant problem after BMT. Relapse is more common after an autologous transplant. This may be due to cancer cells in the transplanted stem cells. Disease recurrence is the major factor related to death more than 3 months after transplant.
Short-term side effects may include nausea, vomiting, fatigue, loss of appetite, mouth sores, hair loss, and skin reactions. Additional side effects may occur. Talk with your doctor for information and details specific to your treatment regimen.
References
Hematopoietic stem cell transplantation. Merck Professional Version website. Available at: http://www.merckmanuals.com/professional/immunology-allergic-disorders/transplantation/hematopoietic-stem-cell-transplantation. Updated August 2018. Accessed December 31, 2018.
Stem cell transplant (peripheral blood, bone marrow, and cord transplants). American Cancer Society website. Available at: http://www.cancer.org/acs/groups/cid/documents/webcontent/003215-pdf.pdf. May 11, 2016. Accessed December 31, 2018.
US patient survival report. Health Resources and Services Administration Blood Cell Transplant website. Available at: http://bloodcell.transplant.hrsa.gov/research/transplant%5Fdata/us%5Ftx%5Fdata/survival%5Fdata/survival.aspx. Accessed December 31, 2018.