Stem cell transplant for myelodysplastic syndrome

Stem cell transplant (SCT) is the only treatment that can cure MDS. In this treatment, the patient receives high-dose chemotherapy and/or total body irradiation to kill the cells in the bone marrow (including the abnormal bone marrow cells). Then the patient receives new, healthy blood-forming stem cells. There are 2 main types of SCT: allogeneic and autologous.

In an autologous stem cell transplant, after the bone marrow is destroyed, the patient gets back their own stem cells. This type of transplant is not a standard treatment for patients with MDS because their bone marrow contains abnormal stem cells.

For an allogeneic stem cell transplant, the patient receives blood-forming stem cells from another person - the donor. The donor’s cells must be matched to the patient’s cell type. The best results are seen when the donor is related to the patient, such as a brother or sister. Less often, the donor is matched to the patient, but is not related. Stem cells for the transplant can be taken from multiple bone marrow samples. More often, the blood-forming stem cells are separated and removed from the peripheral (circulating) blood by a method known as apheresis.

Allogeneic stem cell transplant can have serious, even fatal, side effects and so is rarely used in elderly patients. Because of these side effects, some doctors restrict this treatment to people younger than a certain age.

A special type of allogeneic transplant, called non-myeloablative allogeneic stem cell transplant may be an option for older patients. This type of transplant is sometimes called a mini-transplant or a mini-allo. For this kind of transplant, the doses of chemotherapy and/or radiation that are given are lower than those used for a standard allogeneic transplant. These doses are not high enough to kill all the bone marrow cells, but they are just enough to allow the donor cells to take hold and grow in the bone marrow. The lower doses of chemotherapy and/or radiation cause fewer side effects, but some serious side effects remain, particularly graft-versus-host disease.

Side effects from a SCT are generally divided into early and long-term effects. The early complications and side effects are the same as those caused by any other type of high-dose chemotherapy. They may include:

• Damage to the lungs from radiation (this is rare)
• Damage to the ovaries causes infertility and abrupt menopause, usually with symptoms such as hot flashes and loss of menstrual periods.
• Damage to the thyroid gland may produce problems with metabolism.
• Cataracts, clouding of the lens of the eye that can decrease vision, may occur.

The most serious side effect from allogeneic transplants is called graft-versus-host disease (or GVHD). This occurs when the new immune cells (from the donor) attack the patient’s tissues because they see them as foreign. This is more common if the donor is unrelated or if the cells aren't completely matched. GVHD can occur early in the transplant process – this is called acute GVHD. It can also start later and last a long time - this is called chronic GVHD. Common sites of GVHD include the skin, where it can cause a rash, blistering, or open sores. When GVHD affects the intestines, it can cause diarrhea, which can be severe. It can also cause liver and lung problems. Drugs to suppress the immune system are given as part of the transplant to prevent GVHD. If GVHD develops despite these drugs, additional treatments to suppress the immune system may be needed.

Joint damage called aseptic necrosis is a rare complication; however, if damage is severe, the patient will need to have part of the bone and joint replaced.

Although allogeneic SCT is currently the only treatment that can cure some patients with MDS, not all patients who get a transplant are cured. In addition, patients may die from complications of this treatment. Your chance for cure is higher if you are young and your MDS hasn’t begun to transform into leukemia. Still, doctors recommend waiting until the MDS develops into a more advanced stage before considering transplant.

For more information about stem cell transplants, see our document Stem Cell Transplant (Peripheral Blood, Bone Marrow, and Cord Blood Transplants).