NCCN Guidelines for Patients® | Myelodysplastic Syndromes
35 NCCN Guidelines for Patients ® : Myelodysplastic Syndromes, 2018 4 Cancer treatments Hematopoietic cell transplant Hematopoietic cell transplant An HCT is a treatment that destroys cells in the bone marrow then replaces them with new, healthy blood- forming cells. These blood-forming cells are called blood stem cells or hematopoietic stem cells. Thus, this treatment is also called a stem cell transplant. The goal of an HCT is to cure cancer by replacing unhealthy blood stem cells with healthy ones that will attack cancer cells. This is done by suppressing the bone marrow and cancer with chemotherapy then transplanting healthy blood stem cells. The healthy blood stem cells will grow, form new bone marrow and blood cells, and attack remaining cancer cells. For the treatment of MDS, blood stem cells from a donor are used for the transplant. This is called an allogeneic HCT. Before the transplant, special testing must be done to make sure the donor is a good match for you. HLA typing is used to find a person’s tissue type, called an HLA type. (See page 17 for more details on HLA typing.) An allogeneic HCT creates a new immune system for your body. Another benefit of this transplant is the GVL ( g raft- v ersus- l eukemia) effect. The GVL effect is an attack on the cancer cells by the transplanted blood stem cells. The steps of treatment with an allogeneic HCT are described next. Conditioning treatment Before the transplant, you will receive high-dose- intensity chemotherapy. Reduced-intensity regimens may also be available. This chemotherapy is referred to as conditioning treatment since it prepares (conditions) your body to receive the donated blood stem cells. The chemotherapy destroys normal cells and cancer cells in your bone marrow. It also greatly weakens your immune system so that your body doesn’t kill the transplanted blood stem cells. There are two main types of conditioning treatment that can be used before the HCT. High-dose conditioning consists of high doses of strong (high- intensity) chemotherapy drugs. Reduced-intensity conditioning consists of lower doses of strong chemotherapy drugs or low-intensity drugs. Radiation therapy may also be given as part of conditioning treatment. High-dose conditioning can cause very bad side effects and not all patients can tolerate it. Your doctor will look at a number of factors to decide if you are healthy enough for this treatment. Such factors include your age, your health status, the MDS risk group, and the number of blast cells in your bone marrow. Side effects are often worse in patients who are older or have other serious health problems. Thus, high- dose conditioning is often only used for younger, healthier patients. Reduced-intensity conditioning is often used for patients who are older or less healthy overall. Transplanting the stem cells After the conditioning treatment, the blood stem cells will be put into your body with a transfusion. A transfusion is a slow injection of blood products into a large vein. This process can take several hours to complete. The transplanted blood stem cells then travel to your bone marrow and grow. They will make new, healthy blood cells. This is called engraftment. It usually takes about 2 to 4 weeks. Until then you will have little or no immune defense. This puts you at high risk for infection and bleeding. You will likely need to stay in a hospital in a very clean room for some time. It may take a few weeks or months for blood cells to fully recover so that your immune system goes back to normal.