3P-S4-1

LOW DOSE TBI, INTENSIFIED CHEMOTHERAPY FOLLOWED BY AUTOLOGOUS PERIPHERAL BLOOD STEM CELL TRANSPLANTATION IN CHILDHOOD MALIGNANT TUMORS

Tang Suoqin, Lu Shangen, Peng Yuyun, Ran Chongrong, Wei Xiaojun, Huang Dongsheng,, Zhang Jianzhong

Department of Pediatrics, 301 Hospital, Beijing, China

Objective To investigate the efficacy of low dose TBI (6.0-9.0Gy) combined with intensified chemotherapy followed by autologous peripheral blood stem cell transplantation in childhood malignant tumors.

Methods Twenty one children with malignant tumor have entered this study, male 14, female 7, age 6.1±1.3 years. Underlying disease included high risk-ALL CR1 (n=3), ALL CR2(n=5), AML(n=9), Non-Hodgkin’s lymphoma stage IV(n=2), and neuroblastoma stage IV(n=2). The peripheral hematopoietic stem cells were collected six to eleven months later from complete response, mobilized with high dose chemotherapy alone or combined with GM-CSF or G-CSF. Conditioning regimen was consisting of chemotherapy with several of the following drugs, CTX, Ara-C, McNU, VP16, ID on the basis of TBI (6.0-9.0Gy). A mean of 1.8±0.5×10⁸ autologous mononuclear cells/kg were transplanted. The patients were kept under follow-up after transplant.

Results Peripheral white blood cell count decreased to 0 in all patients at day + 6.8±0.9, severe bone marrow suppression occurred in all patients at day +7. Eight patients died of infection (n=4, +17, +20, +31 and 67 days, respectively) or relapsed (n=3, +5 months, +1.5year, +2 years 10 months, respectively) or intracranial hemorrhage (n=1, +8 months). Thirteen patients have got event free survival for 1.5-11 years, with mean of 5.6±3.1 years.

Conclusion Our preliminary data suggest that meyloablative therapy with low dose TBI (6.0-9.0Gy) combined with intensified chemotherapy might be associated with favorable results in some children with malignant tumor.