A bone marrow transplant is a procedure used to treat certain types of cancer and some other diseases. Before the bone marrow transplant takes place, a person's bone marrow cells are destroyed with radiation or chemotherapy.
The cells that normally live in the bone marrow and that are responsible for making blood cells are then replaced. Bone marrow cells are blood cells that are located in the spongy center of bones. These include:
white blood cells that are important in boosting your immune system and fighting infections
red blood cells that carry oxygen throughout the body
platelets that are necessary for blood clotting
Cells to replace your original cells can be taken from your blood or bone marrow before the procedure starts. Bone marrow cells also can be taken from a different person (a donor) whose cells are a good match for the person receiving the transplant (the recipient). A good match means certain chemical markers on the cells of both donor and recipient are as close as possible and thus minimizes the possibility that the cells will be rejected by your body.
Bone marrow transplants are used most commonly to treat leukemias, lymphomas, Hodgkin's disease, and multiple myeloma. Bone marrow transplantation is particularly helpful, since these diseases affect the bone marrow directly.
Bone marrow transplants also can be used to treat noncancerous conditions, including aplastic anemia, congenital deficiencies of the immune system and thalassemia major. In these conditions, a new bone marrow and new bone marrow cells are needed because the diseased bone marrow is not able to produce necessary cells that may be helpful in fighting the disease to be treated.
Your doctor will discuss your treatment plan, the possible side effects of the procedure and possible complications. If you are a man and you are considering becoming a father, you may want to talk to your doctor about saving some of your sperm because chemotherapy and radiation can cause either temporary or permanent infertility. This is called sperm banking.
You should become totally familiar with all of the support services offered by the medical center where the transplant will be performed.
You will undergo pretreatment evaluation and testing, including many blood tests and other tests, such as a chest X-ray and an echocardiogram.
The next step in a bone marrow transplant is to determine where the replacement cells will come from. There are two options. The cells can be taken from the person having the transplant before the main procedures. This is called an autologous transplant. The other option is for the cells to come from a donor. This is called an allogeneic transplant.
If your own cells will be used, these cells must be collected before your main radiation or chemotherapy begins. There are two ways this can be done.
- Bone marrow harvesting. The cells for the transplant are taken from the patient's bone marrow. The procedure is done in an operating room with you under general anesthesia so you are not awake. A needle and syringe is inserted into the hipbone and is used to withdraw bone marrow.
- Peripheral stem cell harvesting. The cells for the transplant are taken from the patient's circulating blood. A substance called growth factor may be given by injection for several days before the procedure to encourage more stem cells to leave the bone marrow and circulate in the blood. In some cases, chemotherapy is used before the cells are withdrawn to increase the number of circulating stem cells. The procedure is similar to donating blood. A needle will be placed in each of your arms. Blood will flow from one arm through a machine that removes the stem cells. The blood then will be returned to you through the needle in the other arm.
Cells removed either way can be treated to remove any cancer cells, and then stored until the transplant.
If a donor's cells will be used, a donor has to be found whose cells match the patient's cells as closely as possible. It is best if the donor is a close relative because there is a better chance that the cells will match and thus minimize the likelihood of being "rejected." If this is not possible, matching donors sometimes can be found through a bone marrow registry, such as the National Marrow Donor Program in the United States.
A plastic tube called a catheter will be placed into a large vein in your chest with one end sticking through the skin. This will be used to take blood samples and to insert the new cells. Next, you will have the main chemotherapy and radiation as your doctor prescribed. These treatments are designed to treat the underlying condition, but they also cause destruction of the bone marrow cells. Next your transplant cells (which have not been treated with the chemotherapy or radiation) will be put into your bloodstream through the catheter in your chest. Transplant cells will travel through your blood and settle into the spaces where your original cells were. The new cells will multiply. Until they reach a certain level, your body will not be able to fight germs and infections very well, so you will have to stay in the hospital in a special room where you will be protected from germs. This can take several weeks.
You will likely be in the hospital for 4 to 6 weeks following the transplant. For at least some of the time, you will be in a room that is isolated from other patients to help prevent infections.
After you leave the hospital, you will need to return to your doctor's office frequently for several months and you will have several blood tests. The catheter will remain in your chest during that time. When you see your doctor, he or she will check your catheter, examine you for signs of infection and other problems, and review your blood test results.
You also may have tests of your bone marrow to see how well the new cells are growing. This test is called a biopsy. A small sample of your bone marrow is removed through a needle and is examined under a microscope. You also will have tests to see whether any cancer remains.
There are many very serious risks and side effects to a bone marrow transplant. These include:
Severe and continuous bleeding
Infertility or sterility
Numbness in your arms and legs
Secondary cancers. The transplant procedure increases the risk of developing another cancer.
Death. In a very small percent of patients, the complications may lead to overwhelming infections or organ failure despite aggressive attempts to prevent death.
Another possible problem is that cells from a donor might not match your cells well enough and the new cells can begin attacking your cells. This is called graft versus host disease and is a type of "rejection." This can be a serious problem, but it also can help to cure the cancer because the new cells also will attack any cancer cells that are left.
In fact, in some protocols under investigation, donor bone marrow cells are transplanted into recipients who have not had their own bone marrow eliminated. These so-called "mini-transplants" theoretically work well because of the graft-versus-tumor effect. These types of transplants are being investigated mainly for use in situations in which a full transplant may not be possible or where other options are limited.
If you have had a bone marrow transplant, you will be monitored closely for possible complications, and your doctor will tell you what danger signs to watch for. Bone marrow transplant programs are highly specialized and need to be conducted in specially equipped and staffed facilities to minimize the likelihood of complications.
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