Stem Cell Transplantation
Allogeneic stem cell transplantation has been used to treat and sometimes cure patients with MDS. About 40 percent to 50 percent of MDS patients who undergo allogeneic stem cell transplantation are cured of the disease. However, because of the high, sometimes life-threatening risks associated with stem cell transplantation, your doctor's decision to perform a transplant depends mainly on two factors:
- You have intermediate or high-risk MDS according to the International Prognostic Scoring System.
- You have a matched related or unrelated donor.
Although it's not the only type of stem cell transplantation, allogeneic stem cell transplantation is the most common type used to treat MDS. Allogeneic transplantation involves transferring stem cells from a healthy person (the donor) to the patient. The procedure follows high-intensity radiation or chemotherapy, potent drugs that must be toxic enough to kill MDS cells. Unfortunately, the drugs also take aim at normal stem cells in the bone marrow.
The main reasons for doing an allogeneic stem cell transplant are:
- to start a healthy supply of red cells, white cells and platelets with help from the transplanted donor stem cells
- to give strong doses of chemotherapy to kill MDS cells
Stem cell transplantation after radiation or chemotherapy helps to restore marrow function and blood cell production. This gives the initial therapy a chance to better do its work with less damage to your normal cells.
Graft Versus Host Disease
A serious risk of allogeneic stem cell transplantation is graft versus host disease (GVHD), which develops if the donor's immune cells attack your normal tissue. GVHD's effects can range from minor to life threatening.
Reduced-Intensity Allogeneic Stem Cell Transplantation
If you can't tolerate allogeneic transplantation with high-intensity chemotherapy, you may be eligible for reduced-intensity stem cell transplantation (sometimes called nonmyeloablative transplant). This type of transplant is a modified version of allogeneic transplantation being used in clinical trials.
To prepare for the transplant, you undergo less-intense conditioning treatment compared with a standard allogeneic transplant. The chemotherapy destroys most cancer cells with a standard transplant. Reduced-intensity conditioning doesn't destroy many cancer cells but instead relies on the donor's immune cells to fight the disease. This attack is called the graft-versus-tumor (GVT) effect.