A bone marrow transplant is a medical procedure performed to replace bone marrow that has been damaged or destroyed by disease or chemotherapy. This procedure involves transplanting blood stem cells, which travel to the bone marrow where they produce new blood cells and promote growth of new marrow.
Bone marrow is the spongy, fatty tissue inside your bones. It is responsible for creating the following parts of the blood:
- red blood cells, which carry oxygen and nutrients through the body
- white blood cells, which are integral in fighting infection
- platelets, which are responsible for the formation of clots
Bone marrow also contains immature blood-forming stem cells known as hematopoietic stem cells (HSC). Most cells are already differentiated and can only make copies of themselves. However, these stem cells are unspecialized, meaning they have the potential to multiply through cell division and either remain stem cells or differentiate and mature into many different kinds of blood cells. The HSC found in the bone marrow will make new blood cells throughout your lifespan.
A bone marrow transplant replaces your damaged stem cells with healthy cells. This helps your body make enough white blood cells, platelets, or red blood cells to avoid infections, bleeding disorders, or anemia.
Healthy stem cells can come from a donor, or they can come from your own body. In such cases, stem cells can be harvested before a person begins chemotherapy or radiation treatment. Those healthy cells are then stored and used in transplantation.
Bone marrow transplants are performed when a person’s marrow isn’t healthy enough to function properly. This could be due to chronic infections, disease, or cancer treatments. Some reasons for a bone marrow transplant include:
- aplastic anemia (a disorder where the marrow stops making new blood cells)
- cancers that affect the marrow (such as leukemia, lymphoma, and multiple myeloma)
- damaged bone marrow (due to chemotherapy)
- congenital neutropenia (an inherited disorder which causes recurring infections)
- sickle cell anemia (an inherited blood disorder that causes misshapen red blood cells)
- thalassemia (an inherited blood disorder where the body doesn’t make enough red blood cells)
A bone marrow transplant is considered a major medical procedure and increases your risk of experiencing the following symptoms:
- drop in blood pressure
- shortness of breath
While the above symptoms are typically short-lived, bone marrow transplant procedures may cause medical complications. Complications depend on a variety of factors, including:
- your age
- your overall health
- the disease you are being treated for
- the type of transplant
Complications can be mild or very serious, and include:
- graft-versus-host disease (a condition where donor cells attack your body)
- graft failure (when transplanted cells do not begin producing new cells)
- bleeding in the lungs, brain, and other parts of the body
- cataracts (clouding in the lens of the eye)
- damage to vital organs
- early menopause
- anemia (when the body doesn’t produce enough health red blood cells)
- nausea, diarrhea, or vomiting
- mucositis (a condition that causes inflammation and soreness in the mouth, throat, and stomach)
Talk to your doctor about any concerns your may have. He or she can help you weigh the risks and complications against the potential benefits of this procedure.
There are two major types of bone marrow transplants. The type used will depend on the reason you need a transplant.
Autologous transplants use a person’s own stem cells. They typically involve harvesting cells before beginning a damaging therapy like chemotherapy or radiation. After the treatment is done, your own cells are returned to your body.
This type of transplant is not always available. It can only be used if you have healthy bone marrow. However, it reduces the risk of some serious complications, including graft–versus-host disease.
This type of transplant uses cells from a donor. The donor must be a close genetic match. Often, a compatible relative is the best choice, but genetic matches can also be found from a donor registry.
Allogeneic transplants are necessary if you have a condition that has damaged your bone marrow cells. However, they have a higher risk of certain complications, such as graft-versus-host disease. You will also probably need to be put on medications to suppress your immune system so that your body does not attack the new cells. This can leave you susceptible to illness.
The success of an allogeneic transplant depends on how closely the donor cells match your own.
Prior to your transplant, you will undergo several tests to discover what type of bone marrow cells you need.
You may also undergo radiation or chemotherapy to kill off all cancer cells or marrow cells before the new stem cells are given.
Bone marrow transplants take up to a week. Therefore, you must make arrangements before your first transplant session. These can include:
- housing near the hospital for your loved ones
- insurance coverage, payment of bills, and other financial concerns
- care of children or pets
- taking medical leave from work
- packing clothes and other necessities
- arranging travel to and from the hospital
During treatments, your immune system will be compromised. Therefore, you will stay in a special section of the hospital that is reserved for people receiving bone marrow transplants. This reduces your risk of being exposed to anything that could cause an infection.
Do not hesitate to bring a list of questions to ask your doctor. You can write down the answers or bring a friend to listen and take notes. It is important that you feel comfortable and confident before the procedure.
Some hospitals have counselors available to talk with patients. The transplant process can be emotionally taxing. Talking to a professional can help.
When your doctor thinks you are ready, you will have the transplant. The procedure is similar to a blood transfusion.
If you are having an allogeneic transplant, bone marrow cells will be harvested from your donor a day or two before your procedure. If your own cells are being used, they will be retrieved from the stem cell bank.
Cells are collected in two ways:
- bone marrow harvest: cells are collected from both hipbones through a needle. A person is under anesthesia for this procedure, meaning they will be asleep and pain free
- leukapheresis: a donor is given five shots to help the stem cells move from the bone marrow and into the bloodstream. Blood is then drawn through an IV line, and a machine separates out the white blood cells that contain stem cells.
A needle called a central venous catheter, or a port, will be installed on the upper right portion of your chest. This allows the fluid containing the new stem cells to flow directly into your heart. The stem cells then disperse throughout your body. They flow through your blood and into the bone marrow. They will become established there and begin to grow.
The port is left in place because the bone marrow transplant is done over several sessions for a few days. Multiple sessions give the new stem cells the best chance to integrate themselves into your body. That process is known as engraftment.
Through this port you will also receive blood transfusions, liquids, and possibly nutrients. You may need medications to fight off infections and help the new marrow take. This depends on how well you handle the treatments.
During this time, you will be closely monitored for any complications.
The state of your engraftment will be regularly monitored. It is generally complete between 10 and 28 days after initial transplant, according to the Seattle Cancer Care Alliance (SCCA, 2012). The first sign of engraftment is a rising white blood cell count. This shows that the transplant is starting to make new blood cells.
Typical recovery time for a bone marrow transplant is about three months. However, it may take up to a year for you to recover fully. Recovery depends on numerous factors, including:
- the condition being treated
- donor match
- where the transplant is performed
There is a possibility that some of the symptoms you experience post-transplant will remain with you for the rest of your life.
The success of a bone marrow transplant is primarily dependant on how closely the donor and recipient genetically match. Sometimes it can be very difficult to find a good match among unrelated donors. According to the National Marrow Donor Program, the one-year survival rate for bone marrow transplants from unrelated donors was 54 percent between 2002 and 2006 (NMDP, 2009). However, this survival rate increases every year.