In some cases, such as if you have metastatic Ewing sarcoma or the cancer is no longer responding to other treatments, your doctor may recommend a very high dose of chemotherapy to try to kill your cancer cells. High-dose chemotherapy can also destroy bone marrow. Bone marrow is the soft tissue inside your bones where blood stem cells are made. Stem cells help make white and red blood cells and platelets. These cells protect your body from infection, bleeding, and anemia, which is a low red-blood-cell count.
If you are treated with very high doses of chemotherapy, you may need to have a stem cell transplant. With this procedure, the doctor removes some of your stem cells before your high-dose chemotherapy. The stem cells can either be removed from your bone marrow with special needles, or (more often) from your blood by connecting you to a special machine in a process called leukapheresis. These cells are frozen and saved until the doctor is ready to use them for your treatment. When given back to you (as a transfusion), they help your bone marrow recover from the damage from high-dose chemotherapy by greatly assisting in bone marrow healing and recovery (this is often called “stem cell rescue”).
After your chemotherapy, your stem cells are thawed and returned to your body through a vein. The stem cells travel through your bloodstream to your bones. They begin making healthy blood cells within two to three weeks. You may need to stay in the hospital during this time to avoid being exposed to sick people outside the hospital.
A stem cell transplant is a complex treatment that can sometimes have serious side effects because of the high doses of chemotherapy that are used. It is important that the transplant is done at a center that is experienced with this type of treatment. Your doctor or nurse will explain the possible side effects to you before your treatment.