High-Dose Chemotherapy/Radiation Therapy and Stem Cell Transplant for Neuroblastoma

This type of treatment is often used in children with high-risk neuroblastoma who are unlikely to be cured with other treatments. Before the stem cell transplant, a child has usually had about 5 months of intense chemotherapy and might have had surgery to remove the tumor.

Giving higher doses of chemotherapy might be more effective in treating these cancers, but normally this can’t be done because it would cause severe damage to the bone marrow, where new blood cells are made. This could lead to life-threatening shortages of blood cells.

Doctors can sometimes get around this problem by giving the high-dose treatments, then replacing the patient’s bone marrow cells by giving them new blood-making cells (called stem cells). This is known as a stem cell transplant (SCT). Some children might have 2 stem cell transplants, called tandem stem cell transplants.

Collecting stem cells before the transplant

For most children with neuroblastoma, their own stem cells are used for the transplant. These stem cells are collected in a process called apheresis.

To help prepare for stem cell collection, doctors give children a medicine called G-CSF that helps bone marrow make more white blood cells and helps stem cells move into the bloodstream.

G-CSF is usually started at the end of a regular cycle of chemotherapy and is given daily. Children often need blood tests every day once their blood cell counts start to increase (this is often about 7 to 10 days after their first dose of chemotherapy). Once part of the white blood cell count (known as the absolute neutrophil count, or ANC) reaches a certain level, the dose of G-CSF is increased until there are enough stem cells to collect. A special kind of central line will be placed so the stem cells can be collected using apheresis. The collection process is similar to donating blood, but instead of going into a collecting bag, the blood goes into a special machine that filters out the stem cells and returns the other parts of the blood back to the person’s body. Apheresis can take 3 to 4 hours and your child will probably need to lie flat and hold still during the procedure. This process may be repeated over a few days. The stem cells are then frozen until the transplant.

How the transplant is done

Typically, the child will be admitted to the SCT 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 first. This destroys the cancer cells in the body, as well as the normal cells in the bone marrow. After high-dose chemotherapy, the frozen stem cells are thawed and given as a blood transfusion. The stem cells travel through the bloodstream and settle in the child’s bone marrow.

Usually within a couple of weeks, the stem cells begin making new white blood cells. This is later followed by new platelet production and new red blood cell production. Until this happens, the child is at high risk of infection because of a low white blood cell count, as well as bleeding because of a low platelet count. To help lower the risk of infection, the child stays in a special hospital room, and visitors must wear protective clothing. Blood and platelet transfusions and treatment with IV antibiotics may also be used to help prevent or treat infections or bleeding problems.

The child usually stays in the hospital room until part of the white blood cell count rises to a safe level. 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 need to make regular visits to the outpatient clinic for about 6 months, after which time their regular doctors may continue their care.

A SCT is a complex treatment that can cause life-threatening side effects. If the doctors think your child can 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 managing the recovery period.

Possible side effects

The possible side effects from SCT are generally divided into early and 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 or radiation therapy and can be severe. They are caused by damage to the bone marrow and other quickly growing tissues of the body, and can include:

• Low blood cell counts (with fatigue and increased risk of infection and bleeding)
• Nausea and vomiting
• Loss of appetite
• Mouth sores
• Diarrhea
• Hair loss
• Problems with liver

One of the most common and serious short-term effects is an increased risk for serious infections. Antibiotics are often given to try to prevent this. Other side effects, like low red blood cell and platelet counts, might require blood product transfusions or other treatments.

Late or long-term side effects

Some complications and side effects can last for a long time or might not occur until months or years after the transplant. These can include:

• 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

Be sure to talk to your child’s doctor before the transplant to learn about possible long-term effects your child might have. For more on the possible long-term effects of this and other treatments, see the section, Late and Long-term Effects of Neuroblastoma and Its Treatment.

For more information on stem cell transplants in general, see Stem Cell Transplant for Cancer.