'Mini' stem cell transplant: What is it and how does it treat cancer?

August 29, 2014 | by Hiu Chung So

Although a stem cell transplant can be a lifesaving procedure for people diagnosed with a blood cancer or blood disorder, the standard transplant may not be appropriate for all patients. This is because the conditioning regimen (the intensive chemotherapy and/or radiation treatments preceding the transplant) is very taxing on the body, and certain patients — such as those who are older — cannot tolerate the toxicity associated with the process.

Because non-myeloablative transplants rely on the anti-tumor effects of the donor cells, patients can be treated with a lower dose of chemotherapy and/or radiation—resulting in an easier-to-tolerate treatment regimen with fewer side effects. Because nonmyeloablative, or "mini," transplants rely on the anti-tumor effects of the donor cells, patients can be given a lower dose of chemotherapy — resulting in an easier-to-tolerate treatment regimen with fewer side effects.

But at City of Hope, this does not rule them out of a potentially curative transplant, thanks to our care team's specialization in nonmyeloablative transplants (also known as a reduced intensity, or "mini," transplant.)

Here, Stephen J. Forman, M.D., the Francis & Kathleen McNamara Distinguished Chair in Hematology and Hematopoietic Cell Transplantation, explains how this relatively new procedure works.

What is a nonmyeloablativestem cell transplant and how does it work to treat cancer?

Nonmyeloablative stem cell transplant is a way of doing a transplant that is not as intensive as traditional transplant regimens. It uses lower doses of drugs than a standard transplant but still enables us to engraft stem cells from a donor. It then works through utilizing the donor stem cells, which builds an immune reaction against the residual cancer cells — hopefully eliminating the disease and preventing it from returning.

Because it is less intensive, >nonmyeloablative transplants are generally used for patients who are older or otherwise too frail to tolerate a traditional transplant, and this procedure has allowed us to perform curative transplants in a greater range of people.

What patients would be good candidates for this procedure?

This procedure is usually recommended for patients with a hematological malignancy or disorder — such as leukemia, lymphoma, myeloma and myelodysplasia — who are older or otherwise too sick or frail to undergo a traditional transplant. Additionally, their diseases should not be in advanced stages, since it takes some time for the donated stem cells to engraft, mature and react against cancer cells.

What happens to the patient during this treatment?


Stephen J. Forman, M.D. Because a  nonmyeloablative transplant is easier to tolerate than a standard stem cell transplant, it allows older and frailer patients to be treated with this potentially curative procedure, says Stephen Forman.


It is very similar to a traditional transplant in that the patients get a week of chemotherapy and then the stem cell transplant. During this time, they will need protection and immunosuppressive therapy to help prevent against infections and other transplant-related conditions.

Patients will also notice that their blood cell counts will initially drop, but this will go back up again approximately two weeks after the transplant. And when the cell count rises, it is due to the donor cells that will hopefully react against the cancer.

What are the potential side effects of this treatment? How can they be managed?

The side effects of a nonmyeloablative transplant are very similar to a standard transplant. But because the chemotherapy is given at a lower dose, the associated side effects are lower in likelihood and severity, and patients have a better chance of getting through the procedure unharmed.

Like a traditional transplant, there is a risk of graft-versus-host disease (in which the newly transplanted donor cells react against the patient), but this side effect can be prevented or managed with proper monitoring and medication, should it occur.

Is there anything else a patient should know about this therapy?

For patients who ordinarily would not undergo transplant because of their age or condition, this procedure gives them an opportunity for a cure of their disease. Thus, patients who do not qualify for a standard transplant should consult with their doctors about their eligibility for a nonmyeloablative transplant.

Do you have a question for Stephen Forman on nonmyeloablative transplants? If so, post below.


Learn more about becoming a patient at City of Hope by visiting us online or by calling 800-826-HOPE (4673). City of Hope staff will explain what's required for a consult at City of Hope and help you determine, before you come in, whether or not your insurance will pay for the appointment.


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