Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 19 1 2025 01 21 60 68 Tanaz Bahri 1)Cell Therapy and Hematopoietic Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran 2)Research Institute for Oncology, Hematology and Cell Therapy, Tehran University of Medical Sciences, Tehran, Iran Mojtaba Azari Alanjeq Urmia University of Medical Sciences, urmiah, Iran Mohammad Vaezi 1)Research Institute for Oncology, Hematology and Cell Therapy, Tehran University of Medical Sciences, Tehran, Iran 2)Hematology, Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran Ghasem Janbabaei Mollah 1)Research Institute for Oncology, Hematology and Cell Therapy, Tehran University of Medical Sciences, Tehran, Iran 2)Hematologic Malignancies Research Center, Tehran University of Medical Sciences, Tehran, Iran Fatemeh Tajik Rostami 1)Cell Therapy and Hematopoietic Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran 2)Research Institute for Oncology, Hematology and Cell Therapy, Tehran University of Medical Sciences, Tehran, Iran Maryam Barkhordar 1)Cell Therapy and Hematopoietic Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran 2)Research Institute for Oncology, Hematology and Cell Therapy, Tehran University of Medical Sciences, Tehran, Iran Morteza Azari Alanjeq Urmia University of Medical Sciences, Urmiah, Iran Mohammad Biglari 1)Research Institute for Oncology, Hematology and Cell Therapy, Tehran University of Medical Sciences, Tehran, Iran 2)Hematology, Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran Sahar Tavakoli Shiraji 1)Research Institute for Oncology, Hematology and Cell Therapy, Tehran University of Medical Sciences, Tehran, Iran 2)Hematologic Malignancies Research Center, Tehran University of Medical Sciences, Tehran, Iran Soroush Rad 1)Research Institute for Oncology, Hematology and Cell Therapy, Tehran University of Medical Sciences, Tehran, Iran 2)Hematology, Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran Davoud Babakhani 1) Research Institute for Oncology, Hematology and Cell Therapy, Tehran University of Medical Sciences, Tehran, Iran 2)Hematologic Malignancies Research Center, Tehran University of Medical Sciences, Tehran, Iran Mohammadreza Rostami 1)Cell Therapy and Hematopoietic Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran 2)Research Institute for Oncology, Hematology and Cell Therapy, Tehran University of Medical Sciences, Tehran, Iran Seied Asadollah Mousavi 1)Research Institute for Oncology, Hematology and Cell Therapy, Tehran University of Medical Sciences, Tehran, Iran 2)Hematology, Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran Hosein Kamranzadeh Foumani 1) Research Institute for Oncology, Hematology and Cell Therapy, Tehran University of Medical Sciences, Tehran, Iran 2)Hematology, Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran Ardeshir Ghavamzadeh Cancer and Cell Therapy Research Center, Tehran University of Medical Sciences, Tehran, Iran 2024 05 28 2024 10 14 for acute leukemia, though outcomes in older patients remain suboptimal due to higher non-relapse mortality (NRM) and relapse rates. Innovations in conditioning regimens and supportive care have made HSCT accessible to patients over 50, but age-related disparities in outcomes persist. Materials and Methods: This 10-year retrospective cohort study reviewed all patients who underwent first-time allogeneic HSCT for acute leukemia. Patients were stratified by age at HSCT (≥ 50 years and < 50 years), and outcomes were assessed for overall survival (OS), disease-free survival (DFS), NRM, and relapse incidence (RI). Results: Of the 1199 patients, 152 were 50 years or older. Five-year OS rates were markedly lower in patients ≥ 50 years compared to younger patients (48.70% vs. 59.35%; P= 0.024 for AML and 23.60% vs. 41.96%; P= 0.025 for ALL). Moreover, older patients demonstrated significantly higher NRM rates (35.95% vs. 23.53%; P= 0.045 for AML and 78.14% vs. 26.76%; P= 0.005 for ALL) and a notably increased incidence of grade III-IV acute graft-versus-host disease (aGVHD). Interestingly, no significant differences were observed between the two age groups regarding DFS rates and RI. Conclusion: Older acute leukemia patients undergoing allogeneic HSCT face significant challenges, including elevated NRM and GVHD rates. While relapse rates were comparable, survival outcomes favored the younger cohort. These findings emphasize the need for age-adapted transplantation strategies, using reduced-intensity conditioning (RIC) regimens and further research to refine risk stratification and improve management approaches for older patients. https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/2252 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/2252/1067