Stem cells are immature cells that are the starter cells for all types of blood cells. A stem cell transplant uses stem cells to replace bone marrow that contains cancer. These stem cells will grow and become new and healthy bone marrow. The bone marrow with cancer is first destroyed with high-dose chemotherapy. Sometimes this is done along with radiation to the whole body. Healthy stem cells are then put in your body.
A doctor may advise a stem cell transplant in cases like these:
Your leukemia is in remission after induction therapy.
Your leukemia doesn’t go away completely with induction chemotherapy.
Your leukemia returns after a period of remission.
You are young or healthy enough for your body to handle it.
There are 2 kinds of stem cell transplants:
Allogeneic transplant. This means the stem cells come from another person whose cell type is almost exactly like yours. This may be a brother or sister, other family member, or a matched unrelated donor.
Autologous transplant. This means the stem cells are collected from your own body and preserved. This is done before you get the high-dose chemotherapy.
Doctors often prefer to do an allogeneic transplant if a stem cell donor can be found. Doctors might do an autologous transplant if it's hard to find an exact match from a donor. It may cause fewer side effects, but there is also concern that the stem cells from your own body could have some leukemia cells, even after treatment in a lab. Discuss the risks and benefits with your doctor. It's often best to wait for an induced remission and for the chemotherapy side effects to wear off before having a transplant, if possible.
From the blood. This is the most common source of stem cells for a transplant. You or your donor may get an injection of a growth factor medicine for several days. This medicine helps stimulate stem-cell production. The process for collecting stem cells from the blood is called apheresis. It’s a lot like giving blood, but it takes longer. A thin, flexible tube (catheter) is used to get blood from your vein or from a donor. The blood goes to a cell separation device to remove the stem cells. The stem cells are then frozen until needed later. Then the rest of the blood is returned to you or the donor. This process may need to be done more than once to collect the right amount of cells.
From the bone marrow. Stem cells may also be taken from the bone marrow of you or the donor. This process is done while you or your donor is asleep with general anesthesia. A doctor makes several punctures in the pelvic or hip bone to remove marrow. Soreness in the hip bone may last for several days. These stem cells may be and frozen until they are needed.
You may be admitted to the hospital the day before the transplant process begins.
After the chemotherapy or radiation therapy is finished, you will receive the stored stem cells through a needle in your arm. This is similar to a blood transfusion. You may have a strange taste in your mouth during the process. This is from the preservative used to freeze the stem cells.
You will then have to wait for your stem cells to start multiplying. You may have to stay in isolation away from people. This is so that you don’t get an infection. Once part of your white blood cell count (called the absolute neutrophil count) reaches a safe level, you can come out of isolation and then eventually go home. This may happen within several weeks, or it may take longer.
You will need to have your blood drawn often to check your blood cell count for the next few weeks. This can be done on an outpatient basis. This means you go home the same day.
A mini-transplant is sometimes used for a person with AML who can’t handle a standard stem cell transplant. It’s also called non-myeloablative transplant. The treatment is done with a lower dose of chemotherapy or radiation. This doesn't fully destroy the cells in the bone marrow. But it’s enough to suppress the immune system. Then you receive donor stem cells. These stem cells later develop an immune reaction to the remaining leukemia cells in your body and kill them.
Because this treatment uses lower doses of chemotherapy or radiation, it often has less severe side effects. Older adults or people with other health problems can often handle this treatment better.
Most of the short-term side effects of a stem cell transplant are from the high doses of chemotherapy or radiation. These should go away as you recover from the transplant. Common side effects can include:
Low blood cell counts
Low blood pressure
Shortness of breath
Chest pain or tightness
Fever or chills
Loss of appetite
Some side effects of a stem cell transplant may be long-lasting or appear years later, such as:
Growth of another cancer
Damage to the liver, kidneys, or other organs
Lack of menstrual periods, which may mean ovary damage and cause infertility
Vision problems caused by damage to the lens of the eye
Another possible long-term side effect is graft-versus-host disease. This can only occur with an allogeneic transplant. The immune system cells in the donor's stem cells attack your body. The cells can attack your skin, liver, gastrointestinal tract, mouth, or other organs. This can cause symptoms such as:
Skin rashes with itching
Yellowing of the skin (jaundice)
Severe tiredness (fatigue)
It's important to discuss the procedure with your doctor to make sure you understand the possible risks and benefits.