Application of autologous peripheral blood stem cell transplantation in children with malignant tumor

Objective To investigate if low dose total body irradiation (TBI, 6.0 - 9.0 Gy) combined with intensified chemotherapy followed by autologous peripher al blood stem cell transplantation results in better survival in children w ith refractory leukemia or solid tumors. Methods Twenty-one children with malignant tumors were included in this stu dy. There were 14 males and 7 females aged 3.5 - 12 years. Underlying disea se included high-risk acute lymphoblastic leukemia (ALL, CR1 in 3 children and CR2 in 5 children), acute myeloblastic leukemia (AML, 9 children), non- Hodgkin's lymphoma stage IV (2 children), and neuroblastoma stage IV (2 chi ldren). The peripheral hematopoietic stem cells were collected six to eleve n months after complete response, mobilized with high dose chemotherapy alo ne or combined with GM-CSF or G-CSF. The conditioning regimen consisted of chemotherapy with two to three combinations of the following drugs: cycloph osphamide, arabinosylcytosine, McNU, etopside, and Idarubicin on the basis of TBI (6.0-9.0 Gy). A mean of (1.8 +/- 0.5) x 10(8)/kg autologous mononucl ear cells were transplanted. The patients were followed up after transplant ation. Results Severe bone marrow suppression occurred in all patients around day + 7. Peripheral white blood cell count decreased to 0 in all patients at da y + 4.8 +/- 2.9, and platelet count decreased to less than 20 x 10(9)/L at day + 9.0 +/- 2.6. Successful engraftment was achieved in 21 patients, but four died of infection at day + 17, + 20, + 31 and + 67, respectively. Reco very of white blood cell (WBC) to 10 x 109/L, absolute neutrophil count to 0. 5 x 109/L, platelet count to 20 x 109/L occurred on 21 12, 26 +/- 13, an d 27 +/- 10 days, respectively. During the follow up period, three patients relapsed at + 5 months, + 1.5 years, and + 2 years 10 months, respectively . One patient died of intracranial hemorrhage at + 8 months. Thirteen patie nts had event-free survival for 2 - 12 years, with a mean of 6.7 +/- 3.4 ye ars. Conclusion Our preliminary data suggest that myeloablative therapy with low dose TBI (6.0 - 9.0 Gy) combined with intensified chemotherapy followed by autologous peripheral blood stem cell transplantation might be associated with favorable results in children with refractory leukemia or solid tumors .