Abstract: Objective To evaluate the efficacy and safety of unrelated umbilical cord blood transplantation (UCBT) in the treatment of adult patients with hematological malignancies who have a high body weight. Methods A retrospective analysis was conducted on the clinical outcomes of 121 adult patients with hematological malignancies. All patients had a high body weight (≥70 kg) and underwent single-unit UCBT at a single center between January 2018 and September 2024. Results Compared with the low body weight group (<70 kg), the total number of nucleated cells infused was significantly lower in the high body weight group (P<0.01). However, the incidence of pre-engraftment syndrome was significantly higher in the high body weight group [80.83% vs. 69.42% (P<0.01)]. There were no significant differences between the two groups in terms of other post-transplant complications or survival outcomes. Conclusion UCBT is a safe and effective treatment option for adult patients with hematological malignancies who have a high body weight.

Key words: Umbilical cord blood transplantation, Unrelated, High body weight, Hematological malignancies