Total Body Irradiation in Pediatric Patients: Single Center Results

Introduction: Total body irradiation (TBI) with megavolt photon energy is a treatment that can be applied before bone marrow transplantation (BMT) in many hematologic diseases. Two-dimensional TBI (2D-TBI) is one of the oldest RT techniques. We performed a retrospective study to evaluate the radiotherapy (RT)-related acute adverse events in pediatric patients with TBI.
Methods: Patients who received TBI between January 1, 2021, and December 30, 2021, in the Radiation Oncology Clinic of Ankara City Hospital were evaluated retrospectively. The primary endpoint of the study was the assessment of RT-related acute adverse events (RT-AE). The Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 was used for RT-AE.
Results: Twenty-one pediatric patients treated with 2D-TBI between February 20, 2021, and October 10, 2021, have been retrospectively analyzed. The median follow-up period is 7 (range 1–14) months. The median age of the patients is 11 (range 2–17) years. The median time to BMT following TBI is 4 (range 3–13) days. A total of 12 Gy was applied to 15 (71.4%) patients diagnosed with acute lymphoblastic leukemia and acute myeloid leukemia. A total of 3 Gy was applied to 5 (23.8%) patients due to aplastic anemia and thalassemia major. A total of 4 Gy was applied to 1 (4.8%) patient who had anaplastic large cell lymphoma. In the first week after TBI, all 21 (100%) patients were neutropenic in grade 3 or higher. One day after TBI, there was a 23.4% increase in grade 3 or higher leukopenia [p=0.042; OR (95% CI) 0.278 (0.132–0.585)].
Discussion and Conclusion: The 2D-TBI is applied with acceptable toxicity. TBI-related pneumonia was not observed in any of the patients in our treatment technique with a dose/rate of 0.053 Gy/min.

Keywords: Total body irradiation (TBI); Bone Marrow Transplant; Radiotherapy