Bone Marrow Transplants (BMT)

Stem cells are located in the soft, inner portions of certain bones. Stem cells are also out circulating in the blood..

Definition:

A bone marrow transplant, or BMT, is a process to replace unhealthy or ineffective bone marrow cells with a healthy, new population of bone marrow cells.

The bone marrow makes your blood cells – red cells, white cells, and platelets. Stem cells within the marrow are the like the “Adam and Eve” for all these different blood cells. Such stem cells were also later discovered circulating out in the bloodstream, and doctors learned to collect them and use them for transplants, too.

When they do this, it’s called a stem cell transplant, but the old name, BMT, is still sometimes used generally to refer to stem cell transplants.

In people with blood cancer, a transplant can be an important part of effective therapy, leading to a cure in some cases. Expert guidelines have been developed to help with decisions about when a transplant is indicated for different types of leukemia, lymphoma and myeloma.

Types:

The first type, an autologous transplant, uses your own cells, which are collected from the bloodstream or marrow and stored for your transplant. This kind of BMT is planned for in advance, like when you are going to get high doses of strong chemotherapy. Such chemotherapy can destroy cancer cells more effectively, but also may destroy stem cells in the bone marrow. Bone marrow or stem cell transplants help to restore the bone marrow, so that you can tolerate the higher doses of chemotherapy.

The second kind of BMT is called an allogeneic transplant. In this case, you receive bone marrow or stem cells from the bloodstream of another person -- usually a sibling, but sometimes an unrelated donor. (The third type is a syngeneic transplant – that’s what it’s called when you receive stem cells from your identical twin.)

In all cases, after entering the bloodstream, the transplanted cells travel to the bone marrow, where they begin to produce new white blood cells, red blood cells and platelets, a process that may take 10-16 days.

Considerations:

There are a whole host of factors that may determine whether you get an autologous or allogeneic transplant.

Allogeneic transplant:

  • One advantage is that you are starting with fresh, healthy bone marrow that is more surely free of contamination by tumor cells.
  • One disadvantage is the time needed to identify a donor and the limited availability of matching donors for some ethnic groups.

Autologous transplant:

  • One advantage is that there is no need to identify a donor, and since you are using your own cells, you don’t need to suppress your immune system from attacking the donated cells, which means less risk of infection.
  • One disadvantage is that this type of transplant may not be feasible if you don’t have the healthy blood/marrow stem cells needed to for a successful transplant.

    As indicated above, there are many other advantages/disadvantages and considerations involved in determining what type of transplant an individual is likely to receive.

    The Following Terms also Relate to BMT:

    HSCT = hematopoietic stem cell transplantation

    HCT = hematopoietic cell transplantation

    SCT = stem cell transplant

    PBSCT = peripheral blood stem cell transplant (not from bone marrow)

    Sources:

    Deeg HJ, Sandmaier BM. Who is fit for allogeneic transplantation? Blood. 2010;116(23):4762-4770.

    NCCN Clinical Practice Guidelines in Oncology. Acute Lymphoblastic Leukemia. Version 2.2015. Accessed November 2015.

    NCCN Clinical Practice Guidelines in Oncology. Acute Myeloid Leukemia. Version 1.2015. Accessed November 2015.

    NCCN Clinical Practice Guidelines in Oncology. Non-Hodgkin’s Lymphomas. Version 2.2015. Accessed November 2015.

    Updated November 2015. TI

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