Total Body Irradiation (TBI) in Pediatric Patients: A Single-center Experience after 30 Years of Low-dose Rate Irradiation

Purpose: : To retrospectively analyze patient characteristics, treatment, and treatment outcome of pediatric patients with hematologic diseases treated with total body irradiation (TBI) between 1978 and 2006. Patients and Methods: : 32 pediatric patients were referred to the Department of Radiation-Oncology at the University of Zurich for TBI. Records of regular follow-up of 28 patients were available for review. Patient characteristics as well as treatment outcome regarding local control and overall survival were assessed. A total of 18 patients suffered from acute lymphoblastic leukemia (ALL), 5 from acute and 2 from chronic myelogenous leukemia, 1 from non-Hodgkin lymphoma, and 2 from anaplastic anemia. The cohort consisted of 15 patients referred after first remission and 13 patients with relapsed leukemia. Mean follow-up was 34 months (2-196 months) with 15 patients alive at the time of last follow-up. Eight patients died of recurrent disease, 1 of graft vs. host reaction, 2 of sepsis, and 2 patients died of a secondary malignancy. Results: : The 5-year overall survival rate (OS) was 60%. Overall survival was significantly inferior in patients treated after relapse compared to those treated for newly diagnosed leukemia (24% versus 74%; p=0.004). At the time of last follow-up, 11 patients survived for more than 36 months following TBI. Late effects (RTOG ≥3) were pneumonitis in 1 patient, chronic bronchitis in 1 patient, cardiomyopathy in 2 patients, severe cataractogenesis in 1 patient (48 months after TBI with 10 Gy in a single dose) and secondary malignancies in 2 patients (36 and 190 months after TBI). Growth disturbances were observed in all patients treated prepubertally. In 2 patients with identical twins treated at ages 2 and 7, a loss of 8% in final height of the treated twin was observed. Conclusion: : As severe late sequelae after TBI, we observed 2 secondary malignancies in 11 patients who survived in excess of 36 months. However, long-ter