A stem cell transplant uses young blood cells, called stem cells, to replace bone marrow that has been destroyed by cancer treatment. These stem cells will grow, divide, and become new and healthy bone marrow.
Before stem cell transplant, your bone marrow is destroyed with high-dose chemotherapy. Sometimes radiation treatment is given to your whole body, too. The goal is to kill all the cancer cells all over your body, as well as your healthy cells. Then, healthy stem cells are put back in your body. Over time they rebuild your bone marrow and make the healthy blood cells your body needs.
A stem cell transplant is a complex treatment. It can cause serious side effects. Because of this, it's most often used only when lymphoma is no longer responding to treatment. It also may be used if the lymphoma comes back after treatment. A stem cell transplant might be part of the first treatment for some hard-to-treat types of lymphoma.
There are 2 kinds of stem cell transplants:
Allogeneic transplant. This means the stem cells come from another person, called a donor, whose cell type is almost exactly like yours. This may be a close relative such as a brother or sister. The stem cells can also come from a total stranger that closely matches your cell type.
Autologous transplant. This means the stem cells are collected from your own body and saved. This is done before you get chemotherapy.
Autologous transplants are often preferred over allogeneic transplants. This is because there's a lower risk of serious side effects. But autologous transplants have some possible problems, too. For instance, they may not work as well to fully destroy the lymphoma. Most of the time, an allogeneic transplant is done only if an autologous transplant didn’t work. Be sure to discuss the risks and benefits of each with your doctor.
Stem cells may be collected in one of these ways:
From the blood. This is the most common source of stem cells for a transplant. You or your donor get an injection of a growth factor medicine for several days. This medicine helps stimulate stem cell production. Stem cells are then collected from the blood in a process called apheresis. A thin, flexible tube, called a catheter, is used to get blood from your vein or from a donor. The blood goes to a cell separation device where the stem cells are taken out of it. Then the rest of the blood is returned to you or the donor. You may have a strange taste in your mouth during this process. This is from the preservative used to save the stem cells. 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 your bone marrow. Or they may be taken from your donor’s bone marrow. This is done while you or your donor are in a deep sleep with medicines used to make you sleep and not feel pain (general anesthesia). A doctor makes a few small holes in the pelvic or hip bone to remove the marrow. The hip bone may be sore for a few days. These removed stem cells are filtered and frozen until they're needed.
From umbilical cord blood. Stem cells may also be collected from umbilical cord blood. After a baby is born, the blood from the placenta and umbilical cord is collected. This blood has many stem cells. The blood is frozen and stored until it's needed by someone with a matching tissue type.
You'll be admitted to the hospital the day before your transplant. Your treatment team will go over the procedure with you one more time. They will also talk about ways to lower your risk for infections and other possible side effects.
The next morning, you'll start several days of high-dose chemotherapy or radiation.
After cancer treatment is done, you'll get the stored stem cells through an IV (intravenous) line. The bag of stem cells is attached to a tube and they flow into your vein. This is like a blood transfusion. Over time, the stem cells will go to your bone marrow. There, they will start to multiply and make new blood cells.
You will have to wait for your stem cells to start multiplying and growing. This is called engraftment. Engraftment may take 2 to 6 weeks. You might have to stay in the hospital or go to the transplant center every day for the first few weeks. This is to watch you closely and keep you well until your blood cell counts recover.
In some cases, the cancer comes back (relapses) after transplant. If you had an allogeneic transplant, you may be able to get another treatment after the stem cell transplant. This treatment is called DLI (donor lymphocyte infusion). DLI is done by removing a type of white blood cell, called lymphocytes, from the original stem cell donor’s blood and freezing them. The lymphocytes are later thawed and given to you in 1 or more infusions. The donor’s lymphocytes will see any lymphoma cells that are left as not belonging to your body. They will then attack and kill those lymphoma cells.
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 over time as you recover from the transplant. Common side effects can include:
Low blood cell counts
Easy bleeding and bruising
Upset stomach, or nausea
Loss of appetite
Mouth and throat sores
Fever or chills
Shortness of breath
Tightness or pain in the chest
Low blood pressure
Some side effects of a stem cell transplant may be long-lasting or appear years later, such as:
Shortness of breath, often caused by the damage cancer treatment can do to your lungs
Lack of menstrual periods, which may mean ovary damage and cause infertility
Infertility in men
Vision problems such as blurriness or cloudiness, caused by damage to the lens of the eye (cataracts)
Bone pain, caused from damage due to lack of blood supply (aseptic necrosis)
Problems with metabolism, caused by damage to your thyroid gland
Growth of another cancer, such as leukemia, skin, breast, or bone cancer, many years later
Organ damage (the medicines used for transplant can damage organs like your lungs, heart, kidneys, and your muscles and joints.)
Another possible long-term side effect is graft-versus-host disease (GVHD). This can only happen if you had an allogeneic transplant. It's caused when 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 and burning
Upset stomach (vomiting or nausea)
Extreme tiredness, or fatigue
Yellow-colored skin, called jaundice
Your transplant team will talk with you about what you should watch for. It's important to let them know if you notice any changes. GVHD can often be controlled and even prevented.