Peripheral Blood Stem Cell Transplant (PBSCT) in Children With High Risk or Recurrent Solid Tumors

The optimal treatment for refractory (disease won't go away with standard treatment) or relapsed (disease comes back after going away) solid tumors is unknown. Recent studies have shown some benefit to tandem peripheral blood stem cell transplantation (PBSCT). In a tandem transplant, two transplants are done, one after the other. To do a PBSCT, stem cells ("mother cells" that can become any other type of cell) are first collected from the patient's circulating blood. The patient then undergoes high-dose chemotherapy called the preparative regimen. The preparative regimen destroys not only the tumor cells, but it also destroys all of the normal blood making cells. The collected cells are then given back to the patient to "rescue" the patient from the devastating effects of the preparative regimen. By using a stem cell rescue will are able to give much higher doses of chemotherapy than we would be able to give without the stem cell rescue. To make sure that all of the tumor cells are destroyed, patients in this study will undergo two separate transplants using two different preparative regimens. The preparative regimens will use the best agents that have been found to work against recurrent and refractory solid tumors: Busulfan, Thiotepa, Cyclophosphamide and Melphalan.