Bone Marrow Transplantation
Definition of Bone Marrow Transplantation
Article updated and reviewed by Corey Cutler, MD MPH FRCP(C), Instructor in Medicine, Harvard Medical School, Dana-Farber Cancer Institute on May 2, 2005.Bone Marrow Transplantation is replacing or transplanting healthy bone marrow or stem cells to replace bone marrow affected by a malignant condition (cancer) or bone marrow that is responsible for an immune deficiency condition.
Description of Bone Marrow Transplantation
Bone marrow is a soft, liquid-like material found inside most bones. Bone marrow contains a small number of stem cells that are capable of continuously producing all of the elements of blood, including the red cells that carry oxygen, the white cells that fight infections, and the platelets that help blood clot. This is what makes bone marrow the "factory" for the blood and immune system.Bone marrow can sometimes be defective, for example, by not producing enough normal blood cells or by becoming malignant (or cancerous). Doctors long ago realized that if defective bone marrow could be replaced or transplanted with normal marrow from another individual, many lives could be prolonged. But only in the past 25 years has medical knowledge advanced to the point where effective bone marrow transplantation techniques could be developed.
Bone marrow transplantation is accomplished by the intravenous administration of bone marrow or stem cells capable of reproducing themselves and repopulating an empty or defective bone marrow. Often, chemotherapy and/or radiation therapy are required prior to the administration of the stem cells in order to eradicate the remaining defective bone marrow. For patients with cancer, the chemotherapy and radiation therapy also are effective at treating the cancer. Replacing the defective bone marrow of an otherwise healthy person is one use of transplantation techniques, but at least 90 percent of all bone marrow transplants are performed to treat cancer.
The donor for a bone marrow transplant can either be the patient or another individual. When patients donate their own marrow, the marrow is protected from the high doses of chemotherapy and radiation given to treat the cancer. Once the chemotherapy and radiation therapy is completed, the protected bone marrow is given back to the patient. This procedure is called an autologous transplant.
When patients receive bone marrow or stem cells from a donor, the procedure is called an allogeneic transplant. This is usually done in conditions where the bone marrow itself is contaminated with cancer cells. Using another donor guarantees that the new bone marrow is free of cancer. By providing a new immune system to the patient, it is hoped that the new immune system can eradicate any remaining cancer cells that may have survived the chemotherapy and radiation therapy. When using an allogeneic donor, a compatible match must be found. If possible, a brother or sister is generally considered the best donor, but if they are not a suitable match, then a suitable volunteer donor is identified from the national registry.
Stem cells can be collected from the bone marrow itself, can be collected from the blood stream and can be collected from the umbilical cord of a newborn baby. There are advantages and disadvantages to using each one of these types of stem cells.
BMT is now considered to be a standard treatment option for patients with several types of cancer, including the leukemias, lymphomas and multiple myeloma.
Questions To Ask Your Doctor About Bone Marrow Transplantation
Is a bone marrow transplant needed?
What benefits can be expected from a transplant?
How and where does bone marrow come from?
Is there a donor association that is called when bone marrow is needed?
How will the procedure be performed?
How many have you performed?
Will a semi-permanent catheter be inserted?
When will this be done?
What are the risks and side effects?
How long is the hospital stay?
What changes in normal activities will be required?
What supportive care will be available?
________________________________________
Editorial review provided by VeriMed Healthcare Network.
________________________________________
Health Encyclopedia
.gif)
