High-dose chemotherapy and stem cell transplant is not used as the first treatment for non-Hodgkin lymphoma (NHL) in children, but a transplant may be an option if the first treatment does not work or if the lymphoma comes back after treatment.
A stem cell transplant lets doctors give higher doses of chemotherapy than the body would normally tolerate. Giving higher doses of chemo might be more likely to kill all of the lymphoma cells, but doctors can’t do it routinely because it destroys the bone marrow, which is where new blood cells are made. This could lead to life-threatening infections, bleeding, and other serious problems because of low blood cell counts.
For a stem cell transplant doctors first give high doses of chemotherapy and, sometimes, radiation therapy. After the chemotherapy, the child gets a transplant of blood-forming stem cells to restore the bone marrow. These stem cells can be taken either from the child before treatment (autologous stem cell transplant) or donated from another person (allogeneic stem cell transplant).
Autologous stem cell transplant
In an autologous stem cell transplant, blood-forming stem cells are removed from your child’s bone marrow or blood on several occasions in the weeks before treatment. The stem cells are carefully frozen and stored.
Your child then receives high doses of chemotherapy and sometimes radiation treatment to destroy the lymphoma cells, which also destroys the cells in the bone marrow. The frozen stem cells are then thawed and returned to the child as a blood transfusion after the treatment.
For childhood NHL, this type of transplant is done more often than an allogeneic transplant (unless the lymphoma has already reached the bone marrow).
Allogeneic stem cell transplant
In an allogeneic stem cell transplant, the stem cells come from someone else. This type of transplant may be used if lymphoma cells are found in a child’s own bone marrow in order to avoid returning lymphoma cells to the child after treatment.
The stem cell donor’s tissue type (also known as the HLA type) needs to match the patient’s tissue type as closely as possible to help prevent the risk of major problems with the transplant. Usually this donor is a brother or sister if they have the same tissue type as the patient. If a parent is a close match to the child, the parent’s cells can sometimes be used. If there are no relatives with a good match, the cells may come from an HLA-matched, unrelated donor – a stranger who has volunteered to donate their cells – if one can be found.
The stem cells for an allogeneic stem cell transplant are usually collected from a donor’s bone marrow or blood on several occasions. In some cases, the source of the stem cells may be blood collected from an umbilical cord attached to the placenta (which is rich in stem cells) after a baby is born. Regardless of the source, the stem cells are then frozen and stored until they are needed for the transplant.
How stem cells are transplanted
The child will typically be admitted to the stem cell transplant unit of the hospital on the day before the high-dose chemo begins. He or she will usually stay in the hospital until after the chemo and the stem cells have been given, and until the stem cells have started making new blood cells again (see below).
The child gets high-dose chemotherapy and sometimes radiation treatment to the entire body. (Radiation shields are used to protect the lungs, heart, and kidneys from damage during radiation therapy.) This should destroy any remaining cancer cells, as well as the normal cells in the bone marrow.
After treatment, the frozen stem cells are thawed and given as a blood transfusion. The stem cells then travel to the child’s bone marrow. Usually within a couple of weeks after the stem cells have been infused, they begin making new white blood cells. This is later followed by new platelet and red blood cell production.
In the meantime, the child is at high risk for serious infections because of a low white blood cell count, as well as bleeding because of a low platelet count. During this time, blood and platelet transfusions and treatment with IV antibiotics are often used to help prevent or treat infections or bleeding problems.
Because of the high risk of serious infections right after treatment, patients usually stay in a special hospital room in protective isolation (guarding against exposure to germs) until the part of their white blood cell count known as the absolute neutrophil count, or ANC, rises above 500. They may be able to leave the hospital when their ANC is near 1,000.
The child is then seen in an outpatient clinic almost every day for several weeks. Because platelet counts often take longer to return to a safe level, the child may get platelet transfusions as an outpatient. Patients may make regular visits to the outpatient clinic for about 6 months, after which time their care may be continued by their regular doctors.
A stem cell transplant procedure is a complex treatment that can cause life-threatening side effects. If the doctors think your child may benefit from a transplant, the best place to have this done is at a nationally recognized cancer center where the staff has experience with the procedure and with managing the recovery period.
Stem cell transplants often require a long hospital stay and can be very expensive (costing well over $100,000). Be sure to get written approval from your insurer if it is recommended for your child. Even if the transplant is covered by your insurance, co-pays or other costs could easily amount to many thousands of dollars. Find out what your insurer will cover before the transplant so you will have an idea of what you might have to pay.
Possible side effects
The possible side effects from a stem cell transplant are generally divided into early (short-term) and late (long-term) effects.
Early or short-term side effects
The early complications and side effects are basically the same as those caused by high-dose chemotherapy (see the “Chemotherapy” section of this document), and can be severe. They can include:
- Low blood cell counts (with fatigue and increased risks of infection and bleeding)
- Nausea and vomiting
- Loss of appetite
- Mouth sores
- Hair loss
One of the most common and serious short-term effects is the increased risk of serious infections. Antibiotics are often given to try to prevent this. Other side effects, like low red blood cell and platelet counts, may require blood product transfusions or other treatments.
Late and long-term side effects
Some complications and side effects can persist for a long time or may not occur until years after the transplant. These can include:
- Graft-versus-host disease (GVHD), which can occur in allogeneic (donor) transplants (see below).
- Radiation damage to the heart or lungs
- Problems with the thyroid or other hormone-making glands
- Problems with fertility
- Damage to bones or problems with bone growth
- Development of another cancer (including leukemia) years later
GVHD happens when the donor’s immune system cells attack tissues of the patient’s skin, liver, and digestive tract. Symptoms can include severe skin rashes, diarrhea, weakness, fatigue, mouth sores, nausea, yellowing of the skin and eyes (jaundice), and muscle aches. GVHD can also cause lung damage, leading to problems breathing. In severe cases, GVHD can be life-threatening. GVHD is often described as either acute or chronic, based on how soon after the transplant it begins. Drugs that weaken the immune system are often given to try to keep GVHD under control, although they can have their own side effects.
Be sure to talk to your child’s doctor before the transplant to learn about possible long-term effects your child may have. More information on possible long-term effects can be found in the section, “Late and long-term effects of treatment for non-Hodgkin lymphoma in children.”
To learn more about stem cell transplants, see our document Stem Cell Transplant (Peripheral Blood, Bone Marrow, and Cord Blood Transplants).
Last Revised: 01/27/2016