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 no longer responding to standard treatment.
Your leukemia responds to treatment, but returns.
Your leukemia has certain factors that mean it will likely get worse more quickly.
You are younger, healthy enough to tolerate it, or both.
There are 2 kinds of stem cell transplants:
Allogeneic transplant. This means the stem cells come from another person.
Autologous transplant. This means the stem cells are collected from your own body and preserved.
For ALL, stem cells from a matched donor are preferred over using your own stem cells. In many cases this may be a family member, but stem cells may also come from a matched, unrelated donor if no family member has the same tissue type as you.
Doctors typically prefer to do an allogeneic transplant if a suitable stem cell donor can be found. If not, an autologous transplant may be an option. However, there is also concern that the stem cells from your own body could be contaminated with leukemia cells, even after treatment. 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 the transplant, if possible. The following is a general description of how doctors do a stem cell transplant:
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. 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.
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 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 to avoid getting an infection. Once part of your white blood cell count (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 several weeks. This can be done on an outpatient basis.
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 other organs, such as the heart, kidneys, or liver
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 (GVHD). 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)
Damage to the liver, kidneys, or other organs
It's important to discuss the procedure with your doctor to make sure you understand the possible risks and benefits.