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Conditioning regime for stem cell transplantation


Chemotherapy is used to empty the bone marrow space, kill any residual cancer cells and turn off the immune system to prevent rejection of the new stem cells.  This will allow the new stem cells to engraft and eventually produce healthy blood cells.

There are several different chemotherapy medicines or agents.  The chemotherapy agents will be administered through your child’s central line. Your child may receive one or more chemotherapy agents for several days.

Members of the SCT team will discuss your child’s specific chemotherapy agents. There are several potential/possible side effects which will be discussed with you. The diagnostic testing performed before your child’s transplant provides information regarding your child’s ability to handle the chemotherapy medicines.  The SCT team is always monitoring for any side effects.

Total body irradiation

Total body irradiation (TBI) is given to some patients undergoing allogeneic stem cell transplants.  The purpose of radiation therapy is to kill any residual cancer cells and weaken your child's immune system so that rejection of the new marrow is less likely.  The radiation is usually given to the entire body.

An appointment with the radiotherapist will be made one to two weeks before your child’s scheduled admission to assess the amount of radiation your child needs and discuss the treatment and side effects. On the days your child receives TBI, a hospital transportation escort will take your child to the radiation therapy room at MD Anderson Cancer Center. The actual radiation exposure is usually between 5 to 10 minutes twice a day for one to four days.  The procedure involves having your child lie very still on a stretcher for 5-10 minutes. Although your child will have to be alone in the room during the treatment, he/she is being monitored on a TV screen and a two-way intercom.  The procedure is completely painless.  Since it may be difficult for toddlers or small children to be alone and stay still, your child may receive anesthesia during radiation therapy.

General side effects of chemotherapy and radiation

Side effects are the unwanted effects the chemotherapy and radiation have on your child's body.  Some will happen quickly and disappear after several days, while others will occur more gradually and last for several weeks to years.  Large doses of chemotherapy and radiation destroy many of the rapidly dividing cells in the body including abnormal and normal cells.

Areas of the body that have rapidly dividing cells include the skin, hair, and digestive tract. These areas of the body often display early side effects.  Early side effects include hair loss, nausea, vomiting, diarrhea, loss of appetite, skin rashes and changes in the taste of food, oral ulcerations and weight gain. These side effects are temporary and there are medicines available to lessen many of these effects.  Your child’s skin may become darkened or slightly red from radiation therapy.  Your child’s skin will be more sensitive to radiation therapy if any lotions or creams are on the skin during those treatments.  For this reason, do not apply any lotions or creams to your child’s skin during the days he/she receives radiation therapy.

After the chemotherapy and radiation therapy your child will not be able to produce white blood cells, red blood cells or platelets until the new stem cells begins working.  Before your child’s new stem cells can produce new cells, your child have limited ability to fight infections.  Decreased platelets mean your child may bruise or bleed easily.  Platelet transfusions will be given as needed.  Lower hemoglobin levels may make your child feel weak and tired. Red blood cells will also be transfused as needed.