Clinical study of total marrow and lymphatic irradiation in children using helical tomotherapy

Abstract

Objective To evaluate the feasibility of total marrow and lymphatic irradiation (TMLI) with helical tomotherapy as a conditioning regimen before hematopoietic stem cell transplantation (HSCT). Methods Seven children with acute lymphoblastic leukemia and aplastic anemia were recruited as study subjects. The median age was 7 years old. The prescribed dose was 12 Gy/6 fractions twice daily. The exposure dose of the target and the organs at risk between helical helical tomotherapy-based TMLI regimen and total body irradiation (TBI) regimen were statistically compared, and acute toxicity grading was performed for all patients. Results Compared with the TBI regimen, the average exposure dose reduction for organs at risk after the TMLI regimen was ranged from 4.2% to 40.6%.The average exposure dose reduction for the kidney was the largest among all organs. The acute toxicities experienced by all patients were graded and recorded including 2 cases of nausea, 5 cases of vomiting, 1 case of anorexia, 1 case of eryhema, 3 cases of diarrhea, and 1 case of oral mucositis. Only grade 1-2 toxicities were observed, and no grade 3-4 toxicities occurred. Conclusions The findings in this study confirm the feasibility of helical helical tomotherapy-based TMLI regimen. Compared with the TBI regimen, the mean duration of treatment for the TMLI regimen with an equivalent dose is not increased. The exposure dose experienced by organs at risk is reduced and the predicted incidence rate is decreased when the TMLI regimen is employed, which provides a myeloablative pretreatment strategy. However, the long-term toxicity of TMLI regime remains to be evaluated by clinical trials. Key words: Total body irradiation; Total marrow and lymphatic irradiation; Helical tomotherapy; Acute toxicity