Tuesday, December 1, 2015

Here's how 'bone marrow transplants' work

Ask the Expert: The type of cancer, patient's age, general health, availability of donors and other factors determine the type of transplant


Is one person’s bone marrow literally transplanted into another during a bone marrow transplant?


Hematopoietic stem cell transplants (commonly referred to as bone marrow transplants) are typically used to treat blood cancers such as leukemia, lymphoma and multiple myeloma.

Hematopoietic stem cell transplant encompasses peripheral blood stem cell transplant, bone marrow transplant and alternative donor transplant as well. In the majority of cases, the source of the stem cell to complete the transplant is taken from the bloodstream of the patient or a donor (peripheral blood stem cell transplant).

In a smaller number of cases, the patient may receive stem cells from umbilical cord blood or stem cells from a donor’s actual bone marrow.

If the stem cells are taken from the patient, it is called an autologous transplant. If the stem cells are from a donor, it is an allogeneic transplant. Both types of transplants use hematopoietic stem cells that can have the capacity for self-renewal and the ability to form all types of blood cells including red blood cells, white blood cells and platelets.

The stem cells are transfused into the patient’s bloodstream, where they migrate to the bone marrow and grow into healthy new blood cells and therefore repopulate the bone marrow.

In autologous transplants, the dose of chemotherapy is what provides the benefit of disease control/cure. It is more commonly considered as a therapeutic modality for multiple myeloma, where it offers disease control and for recurrent Non-Hodgkin Lymphoma or Hodgkin’s disease where it has the potential for cure.

In allogeneic transplants, the dose of chemotherapy provide benefit but also the interaction between the donor and recipient cells allow a protective response called graft versus tumor effect. It should be noted that each type of transplant is associated with its own risks and benefits.

If an allogeneic transplant is to be performed, a donor search is initiated. Donors have to be closely genetically matched. The donor search usually begins with full blood siblings, who have about a 25 percent chance of being a match (matched-related donor).

For those individuals without a sibling match (70 percent of patients) the search is entered into a registry of donors through the National Marrow Donor Program, where a potential donor is identified (matched-unrelated donor). For those without a full match alternative donor transplants such as umbilical cord or haploidentical transplants (parent or children) may be considered.

The patient’s type of cancer, age, general health, availability of donors, and other factors determine whether an autologous or allogeneic transplant is performed.

The Cancer Transplant Institute at the Virginia G. Piper Cancer Center at HonorHealth has been recognized by the NMDP. It is also one of only 106 U.S. bone marrow transplant centers accredited by the Foundation for the Accreditation of Cellular Therapy for both autologous and allogeneic transplants.

Veena Fauble, MD, is a physician at the Cancer Transplant Institute at the Virginia G. Piper Cancer Center at HonorHealth. For more information about bone marrow transplants available at HonorHealth, please contact an oncology nurse navigator at 480-323-1339 or HonorHealth/cancer.


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