Long-Term Outcomes of Non-Total Body Irradiation Hematopoietic Stem Cell Transplantation in Pediatric Secondary Malignancies: Experience from a Single Center

Secondary malignancies (SMs) are one of the concerning challenges in oncology, referring to the development of a new neoplasm unrelated to the primary tumor. In this study, we evaluated the outcomes of HSCT with a non-total body irradiation (non-TBI) conditioning regimen in 14 pediatric patients with various SMs. Over a 5-year follow-up period after HSCT, the estimated overall survival (OS) and disease-free survival (DFS) rates were 60% and 55%, respectively. Regarding complications, one patient experienced relapse-related mortality, and three others faced HSCT-related mortality. Acute and chronic GVHD occurred in 86% and 36% of patients, respectively. Since TBI is a significant risk factor for developing SMs, particularly in pediatric patients, modifying conditioning regimens for this high-risk group is crucial. Overall, this data offers hope for the effectiveness of using non-TBI HSCT in pediatric patients with SMs as a curative option.