Preparing for the Transplant
When a donor’s stem cells are ready, the person who is having the allogeneic transplant will go through a process known as the preparative regimen. It is also sometimes called conditioning or cytotoxic therapy.
In this step, doctors use chemotherapy with or without radiation therapy to kill the cancer cells in the body. If given in high doses, the treatment can stop the immune system from working as well as it normally does by destroying the blood-forming stem cells in the bone marrow. This process decreases the risk that the patient’s body will reject the donor’s cells. Not everyone can have this kind of treatment, which is called myeloablative or high-dose therapy.
Another way to get ready for a transplant is to give lower doses of chemotherapy with or without low doses of radiation. This type of treatment is called a non-myeloablative or reduced-intensity transplant. People who have this treatment are also given drugs that hold back their immune system, but the treatment doesn’t destroy their stem cells.
For people who have radiation therapy in addition to chemotherapy, Memorial Sloan Kettering researchers have created a less-intensive radiation treatment. This approach is called hyperfractionated radiation. Small doses of radiation are given to the whole body, or to the parts of the body with lymph nodes, two or three times a day over several days, a week, or more. This cuts down on many of the side effects of more-intensive radiation therapy. People usually have the transplant a day or two after their last chemotherapy or radiation dose.
What to Expect During Transplantation and Recovery
After the preparative regimen is done, the transplant can begin. Doctors add the stem cells to the patient’s bloodstream. It is done in the same way as a blood transfusion. In the next few days and weeks, the transplanted stem cells move to the marrow space in the patient’s bones. There, they slowly begin to produce new cells.
Between two and three weeks after the transplant, doctors usually start to find the donor’s cells in the patient’s bloodstream. With time, a successful transplant graft will make red blood cells, white blood cells, and platelets.
In the days right after a transplant, you need a lot of medical support. You may get transfusions of irradiated blood products, such as platelets and red blood cells. You may also get antibiotics to prevent and treat bacterial, viral, and fungal infections. These infections are most likely to happen in the first three months after transplantation. People who have had stem cell transplants may also have complications because of the chemotherapy and radiation given before the transplant. Such complications could require more treatments.
Most people stay in the hospital for two to four weeks after a transplant. During this time, you will need special protection from infection. Everyone who comes in the room has to wear protective gloves and masks and to wash their hands with antiseptic soap. Sometimes people entering the room need to cover their clothing with clean, disposable gowns. Fresh fruit, cut flowers, and plants are not allowed, because they can carry disease-causing mold or bacteria.